X0306 4 2022-03-14 0 0001372020 Great Lakes Dredge & Dock CORP GLDD 0001908351 Lightfoot Todd M C/O GREAT LAKES DREDGE & DOCK CORP. 9811 KATY FREEWAY, SUITE 1200 HOUSTON TX 77024 0 1 0 0 Chief Accounting Officer Common Stock 2022-03-14 4 F 0 1491 14.66 D 12749.534 D Common Stock 2022-03-14 4 A 0 583 A 13332.534 D Common Stock 2022-03-14 5 G 0 E 3101.015 0.00 D 11325.536 D Common Stock 2022-03-14 5 G 0 E 1090 0.00 D 30009.947 I by Trust Common Stock 2022-03-14 5 G 0 E 3101.015 0.00 A 33110.962 I by Trust Represents shares awarded pursuant to satisfaction of performance conditions per the terms of Mr. Lightfoot's performance-based restricted stock units granted on March 12, 2020. Represents a transfer to a revocable trust. The reporting person is trustee of the revocable trust. This filing adds 1,094.076 shares of Common Stock acquired under the Company's Employee Stock Purchase Program. Shares held by the Todd M. Lightfoot Revocable Trust of which Mr. Lightfoot is trustee. /s/Vivienne R. Schiffer, by Power of Attorney 2022-03-16