After her January 1916 commissioning, "Conyngham" sailed off the east coast and in the Caribbean. After the United States entered World War I in April 1917, "Conyngham" was part of the first U.S. destroyer squadron sent overseas. Patrolling the Irish Sea out of Queenstown, Ireland, "Conyngham" made several rescues of passengers and crew from ships sunk by U-boats. "Conyngham"s commander was commended for actions related to what was thought at the time to be a "probable" kill of a German submarine.