Orion Group Holdings Inc

AMENDMENT NO. 2 TO ORION GROUP HOLDINGS, INC.’S

2022 LONG-TERM INCENTIVE PLAN

This Amendment No. 2 (this “Amendment”) to the 2022 Long-Term Incentive Plan the (“2022 LTIP”) is made by Orion Group Holdings, Inc. (the “Company”) pursuant to the 2022 LTIP, as follows:

WHEREAS, the Company previously adopted the 2022 LTIP for the benefit its eligible participants;

WHEREAS, pursuant to Section 10(c) of the 2022 LTIP, the Board of Directors (the “Board”) has the power and authority to amend the terms of the 2022 LTIP, subject to approval by the Company’s stockholders if required;

WHEREAS, this Amendment, which requires the approval by the Company’s stockholders, (i) increases the maximum number of shares of common stock of the Company (“Shares”) that may be issued in connection with awards granted under the 2022 LTIP from 3,735,000 shares to 5,735,000 shares and (ii) expands the application of the per person award limitation to include all members of the Board; and

WHEREAS, the Board approved this Amendment on March 26, 2026.

NOW, THEREFORE, pursuant to the 2022 LTIP, the 2022 LTIP is amended in the following respects:

Section 4(a): Overall Number of Shares Available for Delivery. Subject to adjustment in a manner consistent with any adjustment made pursuant to Section 9, the total number of shares of Stock reserved and available for issuance in connection with Awards under this Plan shall not exceed 5,735,000 shares plus the Stock available under Prior Plans as described in Subsection 4(e).

Section 5: Awards may be granted under this Plan only to Persons who are Eligible Persons at the time of grant thereof or in connection with the severance or retirement of Eligible Persons. In each calendar year, during any part of which this Plan is in effect, an Eligible Person may not be granted (a) Awards (including stock options and SARs but not including any Awards the settlement of which is not based on a number of shares of Stock) relating to more than 2,000,000 shares of Stock, subject to adjustment in a manner consistent with any adjustment made pursuant to Section 9, and (b) Awards the settlement of which is not based on a number of shares of Stock, having a value determined on the date of grant in excess of $5,000,000.00. Subject to the overall limit of Section 4(a) and any adjustments pursuant to Section 9, the maximum number of shares of Stock that may be issued upon the exercise of stock options granted under this Plan that are intended to qualify as ISOs shall be 2,000,000 shares.

2026 Proxy Statement │ 78

IN WITNESS WHEREOF, the Company, by its duly authorized officer, has executed this Amendment on the Effective Date.

By: ________________________________

Name: _____________________________

Title: ______________________________

2026 Proxy Statement │ 79

Signature [PLEASE SIGN WITHIN BOX] Date Signature (Joint Owners) Date TO VOTE, MARK BLOCKS BELOW IN BLUE OR BLACK INK AS FOLLOWS: KEEP THIS PORTION FOR YOUR RECORDS DETACH AND RETURN THIS PORTION ONLY THIS PROXY CARD IS VALID ONLY WHEN SIGNED AND DATED. V92870-P48232 For Withhold ! ! For Against Abstain ! ! ! ! ! ! ! ! ! ! ! 1a. Travis J. Boone 1b. Robert S. Ledford ORION GROUP HOLDINGS, INC. 2940 RIVERBY ROAD, SUITE 400 HOUSTON, TEXAS 77020 VOTE BY INTERNET Before The Meeting - Go to www.proxyvote.com or scan the QR Barcode above Use the Internet to transmit your voting instructions and for electronic delivery of information up until 11:59 P.M. Eastern Time the day before the meeting date. Have your proxy card in hand when you access the web site and follow the instructions to obtain your records and to create an electronic voting instruction form. During The Meeting - Go to www.virtualshareholdermeeting.com/ORN2026 You may only attend the Meeting via the Internet. Have the information that is printed in the box marked by the arrow available and follow the instructions. VOTE BY PHONE - 1-800-690-6903 Use any touch-tone telephone to transmit your voting instructions up until 11:59 P.M. Eastern Time the day before the meeting date. Have your proxy card in hand when you call and then follow the instructions. VOTE BY MAIL Mark, sign and date your proxy card and return it in the postage-paid envelope we have provided or return it to Vote Processing, c/o Broadridge, 51 Mercedes Way, Edgewood, NY 11717. 1. To elect two Class I members to our Board of Directors each to serve a three-year term and until a successor is duly elected and qualified. Nominees: The Board of Directors recommends you vote FOR the nominees, FOR proposal 2, FOR proposal 3, FOR proposal 4 and FOR proposal 5: NOTE: Any other business that may properly come before the Annual Meeting, or any reconvened meeting after an adjournment thereof. 2. A non-binding advisory proposal to approve the compensation of our named executive officers as disclosed in the proxy statement (the “say-on-pay” vote). 4. The approval of a proposed amendment to the Company’s Amended and Restated Certificate of Incorporation to limit the liability of officers as permitted by law. 3. The ratification of the appointment of KPMG LLP as the Company's independent registered public accounting firm for 2026. 5. The approval of a proposed amendment to the Company’s 2022 Long Term Incentive Plan, as amended, to: (i) increase the number of shares of common stock authorized for issuance under the plan by 2,000,000 shares from 3,735,000 shares to 5,735,000 shares; and (ii) expand the per person award limitations thereunder to apply to all Eligible Persons, including all members of the Board. ORION GROUP HOLDINGS, INC. Please sign exactly as your name(s) appear(s) hereon. When signing as attorney, executor, administrator, or other fiduciary, please give full title as such. Joint owners should each sign personally. All holders must sign. If a corporation or partnership, please sign in full corporate or partnership name by authorized officer. ! ! ! SCAN TO VIEW MATERIALS & VOTEw

V92871-P48232 ORION GROUP HOLDINGS, INC. ANNUAL MEETING OF STOCKHOLDERS May 19, 2026 THIS PROXY IS SOLICITED BY THE BOARD OF DIRECTORS OF THE COMPANY Dear Stockholder: You are cordially invited to attend the 2026 Annual Meeting of Stockholders of Orion Group Holdings, Inc. Our 2026 Annual Meeting will be held on Tuesday, May 19, 2026, at 10:00 A.M. Central Time. The Company’s 2026 Annual Meeting of Stockholders will be held in a virtual meeting format only. You will not be able to attend the Annual Meeting physically. You can vote and submit your questions during the meeting via live webcast by visiting www.virtualshareholdermeeting.com/ORN2026. The stockholder(s) hereby appoint E. Chipman Earle as proxy, with the power to appoint his substitute, and hereby authorize(s) him to represent and to vote, as designated on the reverse side of this ballot, all of the shares of Common Stock of ORION GROUP HOLDINGS, INC. that the stockholder(s) is/are entitled to vote at the Annual Meeting of Stockholders to be held on Tuesday, May 19, 2026, at 10:00 A.M. Central Time, via webcast, and any adjournment or postponement thereof. This proxy, when properly executed, will be voted in the manner directed herein. If no such direction is made, this proxy will be voted in accordance with the Board of Directors' recommendations. Continued and to be signed on reverse side Important Notice Regarding the Availability of Proxy Materials for the Annual Meeting: The Notice and Proxy Statement and Annual Report are available at www.proxyvote.com.