After war games off Provincetown, Massachusetts, "Sampson" cleared Tompkinsville, New York on 15 May 1917 to join the escort screen of a convoy which touched at Halifax and reached Queenstown, Ireland, on 25 May 1917. She reported for duty with the United States Naval Forces operating in European waters and was assigned to convoy escort duty in the approaches to the British Isles, basing her operations from Queenstown. Two British-type depth charge projectors were installed on her stern; and, on 29 May, she commenced escort duty and protected the troop transports and merchant convoys from hostile submarines throughout the remainder of World War I.