OCEANEERING INTERNATIONAL INC

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the Securities

Exchange Act of 1934

Filed by the Registrantþ

Filed by a Party other than the Registrant¨

Check the appropriate box:

5875 N. Sam Houston Pkwy. W., Suite 400, Houston, Texas 77086

March 29, 2024

Dear Fellow Shareholder:

You are cordially invited to attend the 2024 Annual Meeting of Shareholders of Oceaneering International, Inc. The meeting will be held on Friday, May 10, 2024, at 8:30 a.m., Central Daylight Saving Time, at 5875 N. Sam Houston Pkwy. W., Houston, Texas 77086.

On the following pages, you will find the Notice of Annual Meeting of Shareholders and Proxy Statement giving information concerning the matters to be acted on at the meeting. Our Annual Report to Shareholders describing Oceaneering’s operations during the year ended December 31, 2023, is enclosed.

We hope you will be able to attend the meeting. Whether or not you plan to attend, please take the time to vote. In addition to using the enclosed paper proxy card to vote, which you may sign, date and return in the enclosed postage-paid envelope, you may vote your shares via the Internet or by telephone by following the instructions included in this package.

Thank you for your continued interest and investment in Oceaneering.

Enclosures

Important Notice Regarding the Availability of Proxy Materials

for the Annual Meeting of Shareholders to Be Held on May 10, 2024

The accompanying Proxy Statement and Annual Report are available under the Filings & Reports tab in the Investors section of our website (www.oceaneering.com).

The following information applicable to the Annual Meeting may be found in the Proxy Statement and/or the accompanying proxy card:

•the date, time and location of the meeting;

•a list of the matters intended to be acted on and our recommendations regarding those matters;

•any control/identification numbers that you need to access your proxy card; and

•information about attending the meeting and voting your shares.

5875 N. Sam Houston Pkwy. W., Suite 400, Houston, Texas 77086

NOTICE OF 2024 ANNUAL MEETING OF SHAREHOLDERS

To the Shareholders of Oceaneering International, Inc.:

The Annual Meeting of Shareholders of Oceaneering International, Inc., a Delaware corporation (“Oceaneering”), will be held at 5875 N. Sam Houston Pkwy. W., Houston, Texas 77086, on Friday, May 10, 2024, at 8:30 a.m., Central Daylight Saving Time, (the “Annual Meeting”).

The meeting will be held for the following purposes:

•elect three Class II directors as members of the Board of Directors of Oceaneering to serve until the 2027 Annual Meeting of Shareholders or until a successor has been duly elected and qualified (Proposal 1);

•cast an advisory vote on a resolution to approve the compensation of Oceaneering’s named executive officers (Proposal 2);

•ratify the appointment of Ernst & Young LLP as independent auditors of Oceaneering for the year ending December 31, 2024 (Proposal 3); and

•transact such other business as may properly come before the Annual Meeting of Shareholders or any adjournment or postponement thereof.

The Board of Directors recommends votes in favor of Proposals 1, 2 and 3.

The close of business on March 20, 2024, is the record date for the determination of shareholders entitled to notice of, and to vote at, the meeting or any adjournment thereof.

Our Board welcomes your attendance at the meeting. Whether or not you expect to attend the meeting, please submit a proxy as soon as possible so that your shares can be voted at the meeting. You may submit your proxy by filling in, dating and signing the enclosed proxy card and returning it in the enclosed postage-paid envelope; or you may vote your shares via the Internet or by telephone. Please refer to page 1 of the Proxy Statement and the proxy card for instructions for proxy voting via the Internet or by telephone.

YOUR VOTE IS IMPORTANT!WHETHER OR NOT YOU PLAN TO ATTEND THE MEETING, PLEASE SUBMIT YOUR PROXY PROMPTLY VIA THE INTERNET OR BY TELEPHONE OR IN THE ENCLOSED POSTAGE-PAID ENVELOPE IN ACCORDANCE WITH INSTRUCTIONS IN THIS PROXY STATEMENT AND ON YOUR PROXY CARD.

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