As filed with the Securities and Exchange Commission on September 7, 2018

Registration No. 333-            

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

AFLAC INCORPORATED

(Exact name of registrant as specified in charter)

Copies to:

Audrey Boone Tillman, Esq.

Executive Vice President &

General Counsel

Aflac Incorporated

1932 Wynnton Road

Columbus, Georgia 31999

(706) 323-3431

Approximate date of commencement of proposed sale to the public: From time to time after the effective date of this registration statement, as determined by market conditions and other factors.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box.  ☐

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, as amended (the “Securities Act”), other than securities offered only in connection with dividend or interest reinvestment plans, check the following box.  ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the SEC pursuant to Rule 462(e) under the Securities Act, check the following box.  ☒

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box.  ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”).

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.  ☐

CALCULATION OF REGISTRATION FEE

PROSPECTUS

Aflac Incorporated

Senior Debt Securities

Subordinated Debt Securities

We may, from time to time, offer to sell senior or subordinated debt securities. This prospectus describes some of the general terms that may apply to these securities.

Specific terms of these securities not provided herein will be provided in one or more supplements to this prospectus. You should read this prospectus and any applicable prospectus supplement carefully before you invest.

You should carefully consider the risks of an investment in these securities. See “Risk Factors” in this prospectus, “Item 1A — Risk Factors” in our most recent Annual Report on Form 10-K and Quarterly Report on Form 10-Q, and any other risk factors included in filings we have made with the Securities and Exchange Commission (the “SEC”) that are incorporated herein by reference or set forth in any applicable prospectus supplement that accompanies this prospectus.

Neither the SEC nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus or any prospectus supplement. Any representation to the contrary is a criminal offense.

The date of this prospectus is September 7, 2018.

TABLE OF CONTENTS

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This prospectus relates to a registration statement filed by Aflac Incorporated with the SEC using a “shelf” registration process (the “registration statement”). Under this shelf process as described in the registration statement, we may sell any combination of the securities described in this prospectus in one or more offerings. This prospectus provides you with a general description of the securities we may offer. Each time we sell securities, we will provide one or more prospectus supplements that will contain specific information about the terms of that particular offering. Any applicable prospectus supplement may also add, update or change information contained in this prospectus. If there is any inconsistency between the information in this prospectus and any applicable prospectus supplement, you should rely on the information in an applicable prospectus supplement. You should read both this prospectus and any applicable prospectus supplement, together with additional information described under the heading “Where You Can Find More Information.”

The functional currency of Aflac Japan’s (as defined below) insurance operations is the Japanese yen. We translate our yen-denominated financial statement accounts into U.S. dollars as follows. Assets and liabilities are translated at end-of-period exchange rates. Realized gains and losses on security transactions are translated at the exchange rate on the trade date of each transaction. Other revenues, expenses and cash flows are translated using average exchange rates for the period. The resulting currency translation adjustments are reported in accumulated other comprehensive income. We include in earnings the realized currency exchange gains and losses resulting from foreign currency transactions.

The registration statement containing this prospectus, including the exhibits to the registration statement, provides additional information about us and the securities to be offered. The registration statement, including the exhibits, can be read at the SEC website or at the SEC offices mentioned under the heading “Where You Can Find More Information.” General information about us, including our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, as well as any amendments and exhibits to those reports, are available free of charge through our website at www.aflac.com as soon as reasonably practicable after we file them with, or furnish them to, the SEC. Information on our website is not incorporated into this prospectus or our other securities filings and is not a part of these filings.

You should rely only on the information contained in this prospectus and the information to which we have referred you. We have not authorized any other person to provide you with information that is different. This prospectus may only be used where it is legal to sell these securities. The information in this prospectus may only be accurate on the date of this document.

As used in this prospectus, unless the context otherwise requires, references to “we,” “us,” “our” or “the Company” refer to the consolidated operations of Aflac Incorporated and its direct and indirect operating subsidiaries. “Parent Company” refers solely to Aflac Incorporated. “Aflac U.S.” refers solely to our subsidiary, American Family Life Assurance Company of Columbus, an insurance company domiciled in Nebraska. “Aflac Japan” refers solely to our subsidiary, Aflac Life Insurance Japan Ltd., a Japanese stock corporation. “Aflac” refers collectively to Aflac U.S. and Aflac Japan.

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

The Private Securities Litigation Reform Act of 1995 provides a “safe harbor” to encourage companies to provide prospective information, so long as those informational statements are identified as forward-looking and are accompanied by meaningful cautionary statements identifying important factors that could cause actual results to differ materially from those included in the forward-looking statements. We desire to take advantage of these provisions. This prospectus or documents filed with the SEC and incorporated by reference herein contain cautionary statements identifying important factors that could cause actual results to differ materially from those projected herein, and in any other statements made by our officials in communications with the financial community and contained in documents filed with the SEC. Forward-looking statements are not based on historical information and relate to future operations, strategies, financial results or other developments. Furthermore, forward-looking information is subject to numerous assumptions, risks and uncertainties. In particular, statements containing words such as “expect,” “anticipate,” “believe,” “goal,” “objective,” “may,” “should,” “estimate,” “intends,” “projects,” “will,” “assumes,” “potential,” “target,” “outlook” or similar words as well as specific projections of future results, generally qualify as forward-looking. We undertake no obligation to update such forward-looking statements.

We caution readers that the following factors, in addition to other factors mentioned from time to time, could cause actual results to differ materially from those contemplated by the forward-looking statements:

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AFLAC INCORPORATED

The Parent Company, Aflac Incorporated, was incorporated in 1973 under the laws of the State of Georgia. The Parent Company is a general business holding company and acts as a management company, overseeing the operations of its subsidiaries by providing management services and making capital available. Its principal business is supplemental health and life insurance, which is marketed and administered through its subsidiaries in the United States and Japan. Most of Aflac’s policies are individually underwritten and marketed through independent agents. Aflac U.S. markets and administers group products through Continental American Insurance Company, branded as Aflac Group Insurance. Our insurance operations in the United States and Japan service the two markets for our insurance business.

We offer voluntary insurance policies in Japan and the United States that provide a layer of financial protection against income and asset loss. We continue to diversify our product offerings in both Japan and the United States. Aflac Japan sells voluntary supplemental insurance products, including cancer plans, general medical indemnity plans, medical/sickness riders, care plans, living benefit life plans, ordinary life insurance plans and annuities. Aflac U.S. sells voluntary supplemental insurance products, including products designed to protect individuals from depletion of assets (accident, cancer, critical illness/care, hospital indemnity, fixed-benefit dental, and vision care plans) and loss-of-income products (life and short-term disability plans).

We are authorized to conduct insurance business in all 50 states, the District of Columbia, several U.S. territories and Japan. Aflac Japan’s revenues, including realized gains and losses on its investment portfolio, accounted for 70% and 69% of our total revenues in the six-month periods ended June 30, 2018 and 2017, respectively. The percentage of our total assets attributable to Aflac Japan was 85% at June 30, 2018, compared with 83% at December 2017.

Our principal executive offices are located at 1932 Wynnton Road, Columbus, Georgia 31999 and our telephone number is (706) 323-3431.

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RISK FACTORS

Investing in our securities involves risk. Please see the risk factors described in “Item 1A — Risk Factors” in our most recent Annual Report on Form 10-K and Quarterly Report on Form 10-Q, which are incorporated by reference in this prospectus, as well as any risk factors included in any other filings we have made with the SEC that are incorporated by reference herein or set forth in any applicable prospectus supplement that accompanies this prospectus. Before making an investment decision, you should carefully consider these risks as well as other information we include or incorporate by reference in this prospectus. The risks and uncertainties we have described are not the only ones we face. Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also affect our business operations, results of operations or financial condition. Additional risk factors may be included in an applicable prospectus supplement relating to a particular series or offering of securities. These risks could materially affect our business operations, results of operations or financial condition and cause the value of our securities to decline. You could lose all or part of your investment.

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USE OF PROCEEDS

Unless otherwise indicated in an applicable prospectus supplement, the net proceeds from the sale of the securities offered by us will be used for general corporate purposes. We may provide additional information on the use of the net proceeds from the sale of the offered securities in an applicable prospectus supplement relating to the offered securities in accordance with SEC rules.

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RATIO OF EARNINGS TO FIXED CHARGES

The following table sets forth our ratio of earnings to fixed charges for each of the periods indicated. For the purpose of computing the below ratios, earnings consist of income from continuing operations before income taxes excluding interest expense on income tax liabilities, plus fixed charges. Fixed charges consist of interest expense, excluding interest expense on income tax liabilities, interest on investment-type contracts and such portion of rental expense as is estimated to be representative of the interest factors in the leases, all on a pre-tax basis.

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DESCRIPTION OF DEBT SECURITIES

Senior Debt Indenture and Subordinated Debt Indenture

We may issue our debt securities, consisting of notes, debentures or other indebtedness, from time to time in one or more series. We will issue any senior debt securities pursuant to the Senior Debt Indenture, dated as of May 21, 2009 between the Parent Company, as issuer, and The Bank of New York Mellon Trust Company, N.A., as trustee (the “Senior Debt Indenture”). We will issue any subordinated debt securities pursuant to the Subordinated Indenture, dated as of September 26, 2012 entered into between the Parent Company, as issuer, and The Bank of New York Mellon Trust Company, N.A., as trustee (the “Subordinated Debt Indenture”). The Senior Debt Indenture and the Subordinated Debt Indenture are incorporated by reference as exhibits to the registration statement of which this prospectus forms a part.

The Senior Debt Indenture and the Subordinated Debt Indenture are substantially similar except that (1) the Subordinated Debt Indenture, unlike the Senior Debt Indenture, provides for debt securities that are specifically made junior in right of payment to other specified indebtedness of the Parent Company and (2) the Senior Debt Indenture, unlike the Subordinated Debt Indenture, restricts the ability of the Parent Company to use the shares of its restricted subsidiaries to secure any indebtedness, unless an equal and ratable security interest in these subsidiary shares is granted to the holders of the senior debt securities. Neither the Senior Debt Indenture nor the Subordinated Debt Indenture limits the aggregate principal amount of indebtedness that we may issue from time to time.

The following description provides a general summary of the material terms and conditions of the Senior Debt Indenture, the Subordinated Debt Indenture and the debt securities to be issued pursuant to these indentures.

The following discussion is only a summary. The indentures may contain language that expands upon or limits the statements made in this prospectus. Accordingly, we strongly encourage you to refer to the indentures, as well as any applicable prospectus supplements for any debt securities offered, for a complete understanding of the terms and conditions applicable to the indentures and the debt securities.

Senior and Subordinated Debt Securities

The debt securities will be our unsecured senior or subordinated obligations. The term “senior” is generally used to describe debt obligations that entitle the holders to receive payment of principal and interest upon the happening of certain events prior to the holders of “subordinated” debt. Events that can trigger the right of holders of senior indebtedness to receive payment of principal and interest prior to payments to the holders of subordinated indebtedness include insolvency, bankruptcy, liquidation, dissolution, receivership, reorganization or an event of default under the Senior Debt Indenture.

We may issue the senior debt securities, pursuant to the Senior Debt Indenture, in one or more series. All series of senior debt securities issued under the Senior Debt Indenture will be equal in ranking. The senior debt securities also will rank equally with all our other unsecured indebtedness, other than unsecured indebtedness expressly designated by the holders thereof to be subordinate to our senior debt securities.

The senior indebtedness issued pursuant to the Senior Debt Indenture will rank junior and be subordinate to any indebtedness of our subsidiaries. In the event of an insolvency, bankruptcy, liquidation, dissolution, receivership, reorganization or similar event involving a subsidiary, the assets of that subsidiary would be used to satisfy claims of policyholders and creditors of the subsidiary rather than our creditors. As a result of the application of the subsidiary’s assets to satisfy claims of policyholders and creditors, the value of the stock of the subsidiary would be diminished and perhaps rendered worthless. Any such diminution in the value of the shares of our subsidiaries would adversely impact our financial condition and possibly impair our ability to meet our obligations on the debt securities. In addition, any liquidation of the assets of the Parent Company’s subsidiaries

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to satisfy claims of the subsidiary’s policyholders and creditors might limit or make it impossible for such subsidiary to pay dividends to us. Any such limitation or inability to pay dividends to the Parent Company would further impair the ability of the Parent Company to satisfy its obligations under the debt securities.

The debt securities issued under the Subordinated Debt Indenture will be subordinate in right of payment in respect of principal, any premium and interest owing under the subordinated debt securities to all the senior indebtedness of the Parent Company in the manner described below under the caption “Subordination Under the Subordinated Debt Indenture.”

Prospectus Supplements

We will provide one or more prospectus supplements to accompany this prospectus for each series of debt securities we offer. In an applicable prospectus supplement, we will describe the following terms and conditions of the series of debt securities that we are offering, to the extent applicable:

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Holders of the debt securities may present their securities for exchange and may present registered debt securities for transfer in the manner described in an applicable prospectus supplement. Except as limited by the applicable indenture, we will provide these services without charge, other than any tax or other governmental charge payable in connection with the exchange or transfer.

Debt securities may bear interest at a fixed rate or a floating rate as specified in an applicable prospectus supplement. In addition, if specified in an applicable prospectus supplement, we may sell debt securities bearing no interest or interest at a rate that at the time of issuance is below the prevailing market rate, or at a discount below their stated principal amount. We will describe in an applicable prospectus supplement the special United States federal income tax considerations applicable to these discounted debt securities.

We may issue debt securities with the principal amount payable on any principal payment date, or the amount of interest payable on any interest payment date, to be determined by referring to one or more currency exchange rates, commodity prices, equity indices or other factors. Holders of such debt securities may receive a principal amount on any principal payment date, or interest payments on any interest payment date, that are greater or less than the amount of principal or interest otherwise payable on such dates, depending upon the value on such dates of applicable currency, commodity, equity index or other factors. An applicable prospectus supplement will contain information as to how we will determine the amount of principal or interest payable on any date, as well as the currencies, commodities, equity indices or other factors to which the amount payable on that date relates and certain additional tax considerations.

Global Debt Securities

We may issue registered debt securities in global form. This means that one “global” debt security would be issued to represent one or more registered debt securities. The denomination of the global debt security would equal the aggregate principal amount of all registered debt securities represented by that global debt security.

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We will deposit any registered debt securities issued in global form with a depositary, or with a nominee of the depositary, that we will name in an applicable prospectus supplement. Any person holding an interest in the global debt security through the depositary will be considered the “beneficial” owner of that interest. A “beneficial” owner of a security is able to enjoy rights associated with ownership of the security, even though the beneficial owner is not recognized as the legal owner of the security. The interest of the beneficial owner in the security is considered the “beneficial interest.” We will register the debt securities in the name of the depositary or the nominee of the depositary, as appropriate.

The depositary or its nominee may only transfer a global debt security in its entirety and only in the following circumstances:

These restrictions on transfer would not apply to a global debt security after the depositary or its nominee, as applicable, exchanged the global debt security for registered debt securities issued in definitive form.

We will describe the specific terms of the depositary arrangement with respect to any series of debt securities represented by a registered global security in an applicable prospectus supplement. We anticipate that the following provisions will apply to all depositary arrangements for debt securities represented by a registered global security.

Ownership of beneficial interests in a registered global security will be limited to (1) participants that have accounts with the depositary for the registered global security and (2) persons that may hold interests through those participants. Upon the issuance of a registered global security, the depositary will credit each participant’s account on the depositary’s book-entry registration and transfer system with the principal amount of debt securities represented by the registered global security beneficially owned by that participant. Initially, the dealers, underwriters or agents participating in the distribution of the debt securities will designate the accounts that the depositary should credit.

Ownership of beneficial interests in the registered global security will be shown on, and the transfer of ownership interests will be effected only through, records maintained by the depositary for the registered global security, with respect to interests of participants, and on the records of participants, with respect to interests of persons holding through participants. The laws of some states may require that purchasers of securities regulated by the laws of those states take physical delivery of the securities in definitive form. Those laws may impair the ability to own, transfer or pledge beneficial interests in registered global securities.

As long as the depositary for a registered global security, or its nominee, is the registered owner of the registered global security, that depositary or its nominee will be considered the sole owner or holder of the debt securities represented by the registered global security for all purposes under the applicable indenture. Owners of beneficial interests in a registered global security generally will not:

Accordingly, each person owning a beneficial interest in a registered global security must rely on the procedures of the depositary for the registered global security and, if that person owns through a participant, on the procedures of the participant through which that person owns its interest, to exercise any rights of a holder under the applicable indenture.

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We understand that under existing industry practices, if we request any action of holders of debt securities or if an owner of a beneficial interest in a registered global security desires to give or take any action that a holder of debt securities is entitled to give or take under the applicable indenture, the depositary for the registered global security would authorize the participants holding the relevant beneficial interests to give or take the action, and the participants would authorize beneficial owners owning through the participants to give or take the action or would otherwise act upon the instructions of beneficial owners owning through them.

We will make payments of principal, any premium and any interest on a registered global security to the depositary or its nominee. None of the Parent Company, the indenture trustee or any other agent of the Parent Company or of the indenture trustee will have any responsibility or liability for any aspect of the records relating to, or payments made on account of, beneficial ownership interests in the registered global security or for maintaining, supervising or reviewing any records relating to the beneficial ownership interests.

We expect that the depositary for any registered global security, upon receipt of any payment of principal, premium or interest in respect of the registered global security, will immediately credit participants’ accounts with payments in amounts proportionate to their respective beneficial interests in the registered global security as shown on the records of the depositary.

We also expect that standing customer instructions and customary practices will govern payments by participants to owners of beneficial interests in the registered global security owned through the participants.

We will issue our debt securities in definitive form in exchange for a registered global security, if the depositary for such registered global security is at any time unwilling or unable to continue as depositary or ceases to be a clearing agency registered under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and if a successor depositary registered as a clearing agency under the Exchange Act is not appointed within 90 days. In addition, we may at any time and in our sole discretion determine not to have any of the debt securities of a series represented by a registered global security and, in such event, will issue debt securities of the series in definitive registered form in exchange for the registered global security.

We will register any debt securities issued in definitive form in exchange for a registered global security in such name or names as the depositary shall instruct the indenture trustee. We expect that the depositary will base these instructions upon directions received by the depositary from participants with beneficial interests in the registered global security.

We also may issue bearer debt securities of a series in global form. We will deposit these global bearer securities with a common depositary or with a nominee for the depositary identified in an applicable prospectus supplement. We will describe the specific terms and procedures of the depositary arrangement for the bearer debt securities in an applicable prospectus supplement. We also will describe in an applicable prospectus supplement any specific procedures for the issuance of debt securities in definitive form in exchange for a bearer global security.

Covenants Applicable to the Debt Securities

Limitations on Liens. Under the Senior Debt Indenture, so long as any debt securities are outstanding, neither we nor any of our restricted subsidiaries may use any voting stock of a restricted subsidiary as security for any of our debt or other obligations unless any debt securities issued under the Senior Debt Indenture are secured to the same extent as and for so long as that debt or other obligation is so secured. This restriction does not apply to liens existing at the time a corporation becomes our restricted subsidiary or any renewal or extension of any such existing lien and does not apply to shares of subsidiaries that are not “restricted subsidiaries.”

To qualify as our “subsidiary,” as defined in the Senior Debt Indenture, we must control, either directly or indirectly, more than 50% of the outstanding shares of voting stock of the corporation. The Senior Debt Indenture

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defines voting stock as any class or classes of stock having general voting power under ordinary circumstances to elect a majority of the board of directors of the corporation in question, except that stock that carries only the right to vote conditionally on the happening of an event is not considered voting stock.

As defined in the Senior Debt Indenture, our “restricted subsidiaries” include (1) Aflac U.S., so long as it remains our subsidiary; (2) any other present or future subsidiary of the Parent Company, the consolidated total assets of which constitute at least 20% of our total consolidated assets (which, as of the date of this prospectus, includes Aflac Japan); and (3) any successor to any such subsidiary.

Consolidation, Merger and Sale of Assets. Both the Senior Debt Indenture and Subordinated Debt Indenture provide that we will not consolidate with or merge into any other person or convey, transfer or lease our assets substantially as an entirety to any person, and no person may consolidate with or merge into us, unless:

This covenant would not apply to the direct or indirect conveyance, transfer or lease of all or any portion of the stock, assets or liabilities of any of our wholly owned subsidiaries to us or to our other wholly owned subsidiaries.

The limitations on the transactions described above do not apply to a recapitalization, change of control, or highly leveraged transaction unless the transaction involves a consolidation or merger into a third party, or a sale, other than for cash to a third party of all or substantially all of our assets, or a purchase by us of all or substantially all of the assets of a third party. In addition, the indentures do not include any provisions that would increase interest, provide an option to dispose of securities at a fixed price, or otherwise protect debt security holders in the event of any recapitalization, change of control, or highly leveraged transaction.

Limitations on Dispositions of Stock of Restricted Subsidiaries. Both the Senior Debt Indenture and Subordinated Debt Indenture provide that, except in a transaction otherwise governed by such indenture, neither we nor any of our restricted subsidiaries may issue, sell, assign, transfer or otherwise dispose of any of the voting stock of a restricted subsidiary so long as any of the debt securities remain outstanding. However, exceptions to this restriction include situations where:

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The indentures do not restrict the transfer of assets from a restricted subsidiary to any other person, including us or another of our subsidiaries.

Events of Default

Unless we provide other or substitute events of default in an applicable prospectus supplement, the following events will constitute an event of default under both the Senior Debt Indenture and the Subordinated Debt Indenture:

If an event of default with respect to any debt securities of any series outstanding under either of the indentures shall occur and be continuing, the trustee under such indenture or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series may declare, by notice as provided in the applicable indenture, the principal amount (or such lesser amount as may be provided for in the debt securities of that series) of all the debt securities of that series outstanding to be due and payable immediately; provided that, in the case of an event of default involving certain events of bankruptcy, insolvency or reorganization, acceleration is automatic; and, provided further, that after such acceleration, but before a judgment or decree based on acceleration, the holders of a majority in aggregate principal amount of the outstanding debt securities of that series may, under certain circumstances, rescind and annul such acceleration if all events of default, other than the nonpayment of accelerated principal, have been cured or waived. Upon the acceleration of the maturity of original issue discount securities, an amount less than the principal amount thereof will become due and payable. Reference is made to an applicable prospectus supplement relating to any original issue discount securities for the particular provisions relating to acceleration of maturity thereof.

Both the Senior Debt Indenture and Subordinated Debt Indenture entitle the trustee to obtain assurances of indemnity or security reasonably satisfactory to it by the debt security holders for any actions taken by the trustee at the request of the security holders. The right of the indenture trustee to obtain assurances of indemnity or security is subject to the indenture trustee carrying out its duties with a level of care or standard of care that is

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generally acceptable and reasonable under the circumstances. An indemnity or indemnification is an undertaking by one party to reimburse another upon the occurrence of an anticipated loss.

Subject to the right of the indenture trustee to indemnification as described above and except as otherwise described in the indentures, the indentures provide that the holders of a majority of the aggregate principal amount of the affected outstanding debt securities of each series, treated as one class, may direct the time, method and place of any proceeding to exercise any right or power conferred in the indentures or for any remedy available to the trustee.

The Senior Debt Indenture and Subordinated Debt Indenture provide that no holders of debt securities may institute any action against us, except for actions for payment of overdue principal, any premium or interest, unless:

Under both the Senior Debt Indenture and Subordinated Debt Indenture, we will file annually with the trustee a certificate either stating that no default exists or specifying any default that does exist.

Discharge, Defeasance and Covenant Defeasance

If indicated in an applicable prospectus supplement, we may discharge or defease our obligations under either the Senior Debt Indenture or the Subordinated Debt Indenture as set forth below.

We may discharge certain obligations to holders of any series of debt securities issued under either the Senior Debt Indenture or the Subordinated Debt Indenture which have not already been delivered to the trustee for cancellation and which have either become due and payable or are by their terms due and payable within one year (or scheduled for redemption within one year) by irrevocably depositing with the trustee cash or, in the case of debt securities payable only in U.S. dollars, U.S. government obligations (as defined in either indenture), as trust funds in an amount certified to be sufficient to pay when due, whether at maturity, upon redemption or otherwise, the principal of (and premium, if any) and interest on such debt securities.

If indicated in an applicable prospectus supplement, we may elect either (i) to defease and be discharged from any and all obligations with respect to the debt securities of or within any series (except as otherwise provided in the relevant indenture) (“defeasance”) or (ii) to be released from our obligations with respect to certain covenants applicable to the debt securities of or within any series (“covenant defeasance”), upon the deposit with the relevant trustee, in trust for such purpose, of money and/or government obligations which, through the payment of principal and interest in accordance with their terms, will provide money in an amount sufficient, without reinvestment, to pay the principal of (and premium, if any) or interest on such debt securities to maturity or redemption, as the case may be, and any mandatory sinking fund or analogous payments thereon. As a condition to defeasance or covenant defeasance, we must deliver to the trustee an opinion of counsel to the effect that the holders of such debt securities will not recognize income, gain or loss for federal income tax purposes as a result of such defeasance or covenant defeasance and will be subject to federal income tax on the same amounts and in the same manner and at the same times as would have been the case if such defeasance or covenant defeasance had not occurred. Such opinion of counsel, in the case of defeasance under clause (i) above, must refer to and be based upon a ruling of the Internal Revenue Service or a change in applicable federal income tax law occurring

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after the date of the relevant indenture. In addition, in the case of either defeasance or covenant defeasance, we shall have delivered to the trustee (i) an officers’ certificate to the effect that the relevant debt securities exchange(s) have informed us that neither such debt securities nor any other debt securities of the same series, if then listed on any securities exchange, will be delisted as a result of such deposit, and (ii) an officers’ certificate and an opinion of counsel, each stating that all conditions precedent with respect to such defeasance or covenant defeasance have been complied with.

We may exercise our defeasance option with respect to such debt securities notwithstanding our prior exercise of our covenant defeasance option.

If we exercise our discharge or defeasance option, payment of the affected debt securities may not be accelerated because of an event of default. If we exercise our covenant defeasance option, payment of the affected debt securities may not be accelerated by reason of a default or an event of default with respect to the covenants that have been defeased. If, however, acceleration of the indebtedness under the debt securities occurs by reason of another event of default, the value of the money and government obligations in the defeasance trust on the date of acceleration could be less than the principal and interest then due on the affected securities because the required defeasance deposit is based upon scheduled cash flow rather than market value, which will vary depending upon interest rates and other factors.

Modification of the Indentures

Both the Senior Debt Indenture and Subordinated Debt Indenture provide that we and the trustee may enter into supplemental indentures without the consent of the holders of debt securities to:

The Senior Debt Indenture and Subordinated Debt Indenture also permit us and the trustee, with the consent of the holders of at least a majority in aggregate principal amount of outstanding affected debt securities of all series issued under the relevant indenture, voting as one class, to change, in any manner, the relevant indenture and the rights of the holders of debt securities issued under that indenture. However, the consent of each holder of an affected debt security is required for changes that:

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The Subordinated Debt Indenture may not be amended to alter the subordination of any outstanding subordinated debt securities without the consent of each holder of then outstanding senior indebtedness that would be adversely affected by the amendment.

Subordination Under the Subordinated Debt Indenture

The Subordinated Debt Indenture provides that payment of the principal, any premium and interest on debt securities issued under the Subordinated Debt Indenture will be subordinate and junior in right of payment, to the extent and in the manner set forth in that indenture, to all our senior indebtedness. The Subordinated Debt Indenture defines senior indebtedness as the principal, any premium and interest on all our indebtedness, whether incurred prior to or after the date of the indenture, which is:

Senior indebtedness also includes all deferrals, renewals, extensions and refundings of, and amendments, modifications and supplements to the indebtedness listed above.

Senior indebtedness does not include:

The Subordinated Debt Indenture does not limit the amount of senior indebtedness that we can incur.

The holders of all senior indebtedness will be entitled to receive payment of the full amount due on that indebtedness before the holders of any subordinated debt securities or coupons relating to those subordinated debt securities receive any payment on account of such subordinated debt securities or coupons, in the event:

We may not make any payment of the principal or interest on the subordinated debt securities or coupons during a continued default in payment of any senior indebtedness or if any event of default exists under the terms of any senior indebtedness.

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Governing Law

The Senior Debt Indenture and the Subordinated Debt Indenture are governed by, and construed in accordance with, the laws of the State of New York, except to the extent that the Trust Indenture Act of 1939, as amended (the “Trust Indenture Act”), is applicable, in which case the Trust Indenture Act will govern.

The Indenture Trustees

The Bank of New York Mellon Trust Company, N.A. is trustee under each of the Senior Debt Indenture and the Subordinated Debt Indenture.

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REGISTRATION, TRANSFER AND PAYMENT OF CERTIFICATED SECURITIES

If we ever issue securities in certificated form, those securities may be presented for registration, transfer and payment at the office of the registrar or at the office of any transfer agent we designate and maintain. The registrar or transfer agent will make the registration or transfer only if it is satisfied with the documents of title and identity of the person making the request. There will not be a service charge for any exchange or registration of transfer of the securities, but we may require payment of a sum sufficient to cover any tax or other governmental charge that may be imposed in connection with the exchange. At any time we may change transfer agents or approve a change in the location through which any transfer agent acts. We also may designate additional transfer agents for any securities at any time.

We will not be required to issue, exchange or register the transfer of any security to be redeemed for a period of 15 days before the selection of the securities to be redeemed. In addition, we will not be required to exchange or register the transfer of any security that was selected, called or is being called for redemption, except the unredeemed portion of any security being redeemed in part.

We will pay principal, any premium, interest and any amounts payable on any certificated securities at the offices of the paying agents we may designate from time to time. Generally, we will pay interest on a security on any interest payment date to the person in whose name the security is registered at the close of business on the regular record date for that payment.

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PLAN OF DISTRIBUTION

We may sell the securities covered by this prospectus in any of three ways (or in any combination) from time to time:

In addition, we may enter into derivative or other hedging transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. If any applicable prospectus supplement so indicates, in connection with such a derivative or other hedging transaction, the third parties may, pursuant to this prospectus and any applicable prospectus supplement, sell securities covered by this prospectus and any applicable prospectus supplement. If so, the third party may use securities borrowed from others to settle such sales and may use securities received from us to close out any related short positions. We may also loan or pledge securities covered by this prospectus and any applicable prospectus supplement to third parties, who may sell the loaned securities or, in an event of default in the case of a pledge, sell the pledged securities pursuant to this prospectus and any applicable prospectus supplement.

Any applicable prospectus supplement will set forth the terms of the offering of the securities covered by this prospectus, including:

Unless an applicable prospectus supplement states otherwise, all amounts payable in respect of the securities, including the purchase price, will be payable in U.S. dollars. Any public offering price or purchase price and any discounts, commissions, concessions or other items constituting compensation allowed or reallowed or paid to underwriters, dealers or agents may be changed from time to time.

Underwriters or the third parties described above may offer and sell the offered securities from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price, at market prices or prices related thereto or at varying prices determined at the time of sale. If underwriters are used in the sale of any securities, the securities will be acquired by the underwriters for their own account and may be resold from time to time in one or more transactions described above. The securities may be either offered to the public through underwriting syndicates represented by managing underwriters, or directly by underwriters. Generally, the underwriters’ obligations to purchase the securities will be subject to certain conditions precedent. The underwriters will be obligated to purchase all of the securities if they purchase any of the securities.

We may sell the securities through agents from time to time. If required by applicable law, any applicable prospectus supplement will name any agent involved in the offer or sale of the securities and any commissions we pay to them. Generally, unless otherwise indicated in any applicable prospectus supplement, any agent will be acting on a best efforts basis for the period of its appointment.

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We may authorize underwriters, dealers or agents to solicit offers by certain purchasers to purchase the securities from us at the public offering price set forth in any applicable prospectus supplement or other prices pursuant to delayed delivery or other contracts providing for payment and delivery on a specified date in the future. Any delayed delivery contracts will be subject only to those conditions set forth in any applicable prospectus supplement, and any applicable prospectus supplement will set forth any commissions we pay for solicitation of these delayed delivery contracts.

Each underwriter, dealer and agent participating in the distribution of any offered securities that are issuable in bearer form will agree that it will not offer, sell, resell or deliver, directly or indirectly, offered securities in bearer form in the United States or to U.S. persons except as otherwise permitted by Treasury Regulations Section 1.163-5(c)(2)(i)(D).

Offered securities may also be offered and sold, if so indicated in any applicable prospectus supplement, in connection with a remarketing upon their purchase, in accordance with a redemption or repayment pursuant to their terms, or otherwise, by one or more remarketing firms, acting as principals for their own accounts or as agents for us. Any remarketing firm will be identified and the terms of its agreements, if any, with us and its compensation will be described in any applicable prospectus supplement.

Agents, underwriters and other third parties described above may be entitled under relevant underwriting or other agreements to indemnification by us against certain civil liabilities under the Securities Act of 1933, as amended (the “Securities Act”) or to contribution with respect to payments which the agents, underwriters or other third parties may be required to make in respect thereof. Agents, underwriters and such other third parties may be customers of, engage in transactions with, or perform services for us in the ordinary course of business.

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WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the SEC under the Exchange Act. You may read and copy any of this information at the SEC’s Public Reference Room at 100 F Street, N.E., Washington, D.C. 20549. You may obtain information on the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0330. The SEC also maintains an Internet site that contains reports, proxy and information statements and other information about issuers who file electronically with the SEC. The address of that site is http://www.sec.gov. These reports, proxy statements and other information may also be inspected at the offices of the NYSE at 20 Broad Street, New York, New York 10005. General information about us, including our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, as well as any amendments and exhibits to those reports, are available free of charge through our website at www.aflac.com as soon as reasonably practicable after we file them with, or furnish them to, the SEC. Information on our website is not incorporated into this prospectus or our other securities filings and is not a part of these filings.

This prospectus relates to a registration statement that we have filed with the SEC relating to the securities to be offered. This prospectus does not contain all of the information we have included in the registration statement and the accompanying exhibits and schedules in accordance with the rules and regulations of the SEC and we refer you to the omitted information. The statements this prospectus makes pertaining to the content of any contract, agreement or other document that is an exhibit to the registration statement necessarily are summaries of their material provisions and do not describe all exceptions and qualifications contained in those contracts, agreements or documents. You should read those contracts, agreements or documents for information that may be important to you. The registration statement, exhibits and schedules are available at the SEC’s public reference room or through its website.

We “incorporate by reference” into this prospectus information we file with the SEC, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is deemed to be part of this prospectus and later information that we file with the SEC will automatically update and supersede that information. This prospectus incorporates by reference the documents set forth below that we have previously filed with the SEC. These documents contain important information about us and our financial condition.

The following documents listed below, which we have previously filed with the SEC, are incorporated by reference:

All documents filed by us under Section 13(a), 13(c), 14 or 15(d) of the Exchange Act from the date of this prospectus and prior to the termination of the offering of the securities shall also be deemed to be incorporated in this prospectus by reference.

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We will provide a copy of these filings, at no cost, upon your written or oral request to us at the following address or telephone number:

Aflac Incorporated

Office of the Secretary

1932 Wynnton Road

Columbus, Georgia 31999

(706) 323-3431

Exhibits to the filings will not be sent, unless those exhibits have been specifically incorporated by reference in this prospectus.

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LEGAL MATTERS

Unless otherwise indicated in an applicable prospectus supplement, certain legal matters as to Georgia law in connection with the offering of the debt securities will be passed upon for us by Audrey Boone Tillman, Esq., Executive Vice President and General Counsel of Aflac Incorporated and certain legal matters as to New York law in connection with the offering of the debt securities will be passed upon for us by Sidley Austin LLP, New York, New York. Additional legal matters may be passed on for us, or any underwriters, dealers or agents, by counsel which we will name in an applicable prospectus supplement.

EXPERTS

The consolidated financial statements and schedules of Aflac Incorporated and subsidiaries as of December 31, 2017 and 2016, and for each of the years in the three-year period ended December 31, 2017, and management’s assessment of the effectiveness of internal control over financial reporting as of December 31, 2017 have been incorporated by reference herein in reliance upon the reports of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing.

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PART II.

INFORMATION NOT REQUIRED IN PROSPECTUS

The expenses in connection with the issuance and distribution of the securities being registered, other than underwriting compensation, are set forth in the following table. Each amount shown is estimated.

The Georgia Business Corporation Code permits a corporation to indemnify a director or officer if the director or officer seeking indemnification acted in good faith and reasonably believed (i) in the case of conduct in his or her official capacity, that his or her action was in the best interest of the corporation, (ii) in all other cases, that his or her action was at least not opposed to the best interests of the corporation, and (iii) in the case of any criminal proceedings, that he or she had no reasonable cause to believe his or her conduct was unlawful, provided that indemnification in connection with a proceeding by or in the right of the corporation is limited to reasonable expenses incurred in connection with the proceeding. The Georgia Business Corporation Code prohibits indemnification of a director in connection with a proceeding by or in the right of the corporation (other than for reasonable expenses) if it is determined that the director has not met the relevant standard of conduct, or with respect to conduct for which he or she was adjudged liable on the basis that a personal benefit was improperly received by him or her, whether or not involving action in his or her official capacity. The Georgia Business Corporation Code additionally prohibits indemnification of an officer for liability arising in connection with appropriation of a business opportunity of the corporation, intentional or knowing violation of law, improper distributions or improper personal benefit.

Aflac Incorporated’s articles of incorporation provide that, to the fullest extent permitted by Georgia law, as the same exists or may be hereafter amended, no director of Aflac Incorporated shall be personally liable to Aflac Incorporated for monetary damages for any breach of the duty of care or other duty as a director, provided that Aflac Incorporated’s articles of incorporation do not limit or eliminate liability for (i) a breach of duty involving an appropriation of a business opportunity of Aflac Incorporated; (ii) an act or omission not in good faith or involving intentional misconduct or a knowing violation of law; (iii) any action for which a director could be found liable pursuant to Section 14-2-154 of the Georgia Business Corporation Code, or any amendment or successor provision of such section; and (iv) any transaction from which the director derived an improper personal benefit. In addition, a director’s liability will not be limited as to any payment of a dividend or approval of a stock repurchase that is illegal under Section 14-2-640 of the Georgia Business Corporation Code.

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Aflac Incorporated maintains (i) director and officer liability insurance that provides for indemnification of the directors and officers of Aflac Incorporated and of its majority-owned subsidiaries, and (ii) company reimbursement insurance that provides for indemnification of Aflac Incorporated and its majority-owned subsidiaries in those instances where the Parent Company and/or its majority-owned subsidiaries indemnified its directors and officers.

Exhibit Index

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The undersigned Registrant hereby undertakes:

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) to include any prospectus required by Section 10(a)(3) of the Securities Act;

(ii) to reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the SEC pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

(iii) to include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

provided, however, that paragraphs (i), (ii) and (iii) above do not apply if the information required to be included in a post-effective amendment by those clauses is contained in reports filed with or furnished to the SEC by the Registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934, as amended, that are incorporated by reference in this registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

(2) That, for the purpose of determining any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(4) That, for the purpose of determining liability under the Securities Act to any purchaser:

(i) Each prospectus filed by the Registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

(ii) Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5) or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii) or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which the prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof; provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date.

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(5) That, for the purpose of determining liability of the Registrant under the Securities Act to any purchaser in the initial distribution of the securities: the undersigned Registrant undertakes that in a primary offering of securities of the undersigned Registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned Registrant will be seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i) Any preliminary prospectus or prospectus of the undersigned Registrant relating to the offering required to be filed pursuant to Rule 424;

(ii) Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned Registrant or used or referred to by the undersigned Registrant;

(iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned Registrant or its securities provided by or on behalf of the undersigned Registrant; and

(iv) Any other communication that is an offer in the offering made by the undersigned Registrant to the purchaser.

(6) That for purposes of determining any liability under the Securities Act, each filing of the Registrant’s annual report pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(7) To file an application for the purpose of determining the eligibility of the trustee to act under subsection (a) of Section 310 of the Trust Indenture Act in accordance with the rules and regulations prescribed by the SEC under Section 305(b)(2) of the Trust Indenture Act.

Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and persons controlling of the Registrant pursuant to the foregoing provisions, the Registrant has been advised that in the opinion of the SEC such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the Registrant of expenses incurred or paid by a director, officer or controlling person of the Registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the Registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

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SIGNATURES

Pursuant to the requirements of the Securities Act, Aflac Incorporated certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Columbus, Georgia, on this 7th day of September, 2018.

POWER OF ATTORNEY

We, the undersigned officers, directors and authorized representatives of Aflac Incorporated, hereby severally constitute and appoint Audrey Boone Tillman and J. Matthew Loudermilk, and each of them the lawful attorneys and agents, with full power of substitution and authority, to sign for us and in our names in the capacities indicated below, the registration statement on Form S-3 filed herewith and any and all pre-effective and post-effective amendments to said registration statement, and any subsequent registration statement for the same offering which may be filed under Rule 462(b), and generally to do all such things in our names and on our behalf in our capacities as officers and directors to enable Aflac Incorporated to comply with the provisions of the Securities Act, as amended, and all requirements of the SEC, hereby ratifying and confirming our signatures as they may be signed by our said attorney, or his substitute or substitutes, to said registration statement and any and all amendments thereto or to any subsequent registration statement for the same offering which may be filed under Rule 462(b).

Pursuant to the requirements of the Securities Act, this registration statement has been signed by the following persons in the capacities and on the dates indicated.

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