WASHINGTON—The Department of Homeland Security said Friday it would provide businesses another 15,000 H-2B visas to bring low-skilled foreign workers to the U.S. this summer, offering a modest infusion to the popular program.

The number of visas available each year for seasonal work is capped by statute at 66,000, evenly divided between the summer and winter seasons. Congress declined to lift that cap during negotiations this spring. It did, however, give the secretary of homeland security authority to issue up to 69,000...