Cepheus put to sea from Staten Island 27 February 1944, bound in convoy for Liverpool. Although several submarine contacts were reported in the convoy, effective work by the escorts prevented any attacks, and the convoy arrived safely 9 March, with its cargo destined for the Normandy invasion. Joining her assigned division in Scottish waters, Cepheus sailed for Oran, where she arrived 6 April to report to the Eighth Amphibious Force. After training exercises along the Algerian coast, she loaded vehicles and troops for the passage to Naples, where she unloaded 19 June to 23 June. After training at Palermo and Salerno, she returned to Naples to offload combat vehicles, then cleared for Castellammare near Palermo to combat load for the invasion of Southern France.
Cepheus put to sea with the Camel Beach Attack Group 13 August 1944, and after a safe passage along a route designed to camouflage the convoy's destination, arrived off the beaches east of Saint Raphael just before dawn of 15 August. Her swift and competent unloading was a significant contribution to the successful passage over those beaches, and although the latter stages of unloading were accomplished under enemy air attack and through defensive smoke screen, Cepheus was empty before midnight, and moved out to await orders for her return to Naples, where she arrived on 18 August.
Between 23 August and 7 October 1944, Cepheus supported the rapid advance of forces ashore by four more voyages, two from Naples to the assault area, and two from Oran to Marseilles, captured at the end of August after heavy naval bombardment of its defenses. Clearing Oran in convoy 25 October, she arrived at Norfolk, Va., 8 November. Here she prepared for duty in the Pacific, and on 18 December was underway for Pearl Harbor with cargo.
Pacific, 1945–1946
Arriving 10 January 1945, she joined in training exercises until 26 February, when she put to sea combat loaded for the Okinawa assault. Cepheus arrived in the transport area off Okinawa on 1 April 1945, and since her cargo was destined for use after the initial assault, sent her boats for use in unloading three other transports. She retired seaward for the night, and came under enemy air attack while returning to the island next morning. During that raid, she fired upon seven Japanese aircraft, and aided in downing three. She remained off the island, unloading and aiding other ships to unload, firing on enemy aircraft, until 16 April, when she cleared for replenishment at Saipan. Through May and June, she made a voyage from the Marianas to New Zealand to load cargo, and on 12 July, returned to Ulithi to join an Okinawa-bound convoy. At Hagushi anchorage, she underwent several air attacks, then moved to Kerama Retto to unload. She returned to New Caledonia and the New Hebrides to load construction equipment, which she carried to the Philippines, arriving at Lingayen 16 September. Four days later, she put to sea for the first of two voyages from the Philippines to Japan with occupation supplies, and on 28 October, she cleared for Portland, Oregon, from Hiro Wan. One more voyage was made from the west coast to the Far East, during which Cepheus carried cargo to Tientsin, China, before 15 February 1946, when the cargo transport left San Francisco astern, bound for New York City. Here she was decommissioned 22 May 1946, and returned to the Maritime Commission. MARAD records show she was given back to the Navy on 21 November 1946 and a "reconversion" contract was awarded to Maryland Drydock Company on 2 May 1947.[1]
Cepheus received two battle stars for World War II service
Commercial service
Cepheus was sold into commercial service in 1947. In 1968, while being on a ballast voyage home from Sattahip, Thailand to Tampa, Florida, she ran aground at full speed on a reef off Honduras and was heavily damaged. Refloating proved to be impossible and she was finally abandoned as a constructive total loss in June 1968.