Roamer was built as a civilian steam launch of the same name in 1902 by Herreshoff Manufacturing Company at Bristol, Rhode Island. On 29 June 1917, the U.S. Navy acquired her from the State of Florida at Tallahassee, Florida, for use as a section patrol boat during World War I. She was commissioned on 20 July 1917 as USS Roamer (SP-1047) with Ensign T. R. Hodges, USNRF, in command. Assigned to the 8th Naval District, Roamer carried out patrol duties for the rest of World War I.