Swan, a minesweeper, was laid down at Mobile, Alabama, on 10 December 1917 by the Alabama Dry Dock & Shipbuilding Co.; launched on Independence Day 1918; sponsored by Miss Hazel Donaldson; and commissioned at New Orleans, Louisiana, on 31 January 1919, Lt. (jg.) Fredman J. Walcott, USNRF, in command.