Originally laid down as SS Mission San Xavier, a Maritime Commission T2-SE-A2 tanker (MC hull 1826) by the Marinship Corporation of Sausalito, California on 18 May 1944; renamed USS Pasig (AO–91) on 3 July 1944; launched on 15 July 1944, sponsored by Mrs. John A. McCone; redesignated USS Pasig (AW–3) on 28 August 1944; acquired by the Navy from the Maritime Commission on 21 October 1944; and commissioned on 11 December 1944 with Lieutenant Commander Clarke M. Williams in command.