144 0001363032 XXXXXXXX LIVE 0001372020 Great Lakes Dredge & Dock CORP 001-33225 9811 KATY FREEWAY SUITE 1200 HOUSTON TX 77024 (346) 359-1010 Levenson Ryan Former Director Common Fidelity Brokerage Services LLC

900 Salem Street Smithfield RI 02917

21160 193576.22 67009319 05/23/2024 NASDAQ Common 05/13/2024 Restricted Stock Vesting Issuer N 21160 05/13/2024 Compensation N Ryan J. Levenson

9811 Katy Freeway Suite 1200 Houston TX 77024

Common 05/22/2024 19710 182512.36 05/23/2024 /s/ Gary Redman, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Ryan J. Levenson