August 4, 2008

Great Lakes Dredge & Dock Corporation Schedules Announcement for 2008 Second Quarter Results

Great Lakes Dredge & Dock Corporation (NASDAQ: GLDD) today announced that it will release its financial results for the quarter and six months ended June 30, 2008 on Thursday, August 7, 2008 at 7:00 a.m. C.D.T. A conference call with the Company will be held the same day at 10:00 a.m. C.D.T. The call in number is 877-419-6598. The call can also be heard on the Company's website, under Events and Presentations on the investor relations page. The conference call will be available by replay for two weeks, by calling 888-203-1112 and providing passcode 7293742. A copy of the press release will be available on the Company's website.

Great Lakes Dredge & Dock Corporation is the largest provider of dredging services in the United States and the only U.S. dredging company with significant international operations, averaging 23% of the Company's total dredging revenue over the last three years. Great Lakes is a leader in each of the U.S. markets in which it competes: capital, maintenance and beach nourishment dredging. The Company is also one of the largest U.S. providers of commercial and industrial demolition services. Additionally, the Company owns a 50% interest in a marine sand mining operation in New Jersey which supplies sand and aggregate used for road and building construction. Great Lakes has a 118-year history of never failing to complete a marine project and owns the largest and most diverse fleet in the industry, comprised of over 180 specialized vessels.