The U.S. Navy purchased the Conestoga in September 1917 after the United States entered World War I. It carried out towing duties along the Atlantic coast and at the end of the war it was attached to Naval Base No. 13, Azores. After the war it was assigned to harbor tug duty at Norfolk, Virginia. It was reclassified USS Conestoga AT 54 in 1920 and after undergoing alterations, it was ordered to duty as a station ship in American Samoa, but disappeared on its way after departing San Francisco.