USS Mona Island (ARG-9) was laid down on 10 April 1944, as a Maritime Commission type (EC2-S-C1) hull, under Maritime Commission contract (MC hull 2634) at Bethlehem Fairfield Shipyard, Inc., Baltimore, Maryland. Launched on 11 May 1944. Acquired by the U.S. Navy from the Maritime Commission and converted to Internal Combustion Engine Repair Ship (ARG-9) at Maryland Drydock Co, Baltimore, Maryland, and commissioned USS Mona Island (ARG-9), on 17 October 1944, CDR K. F. Horne in command.