Upon being commissioned, "Bougainville" got underway, on 7 July, on a shakedown cruise down the West Coast to San Diego. Upon arriving, she was assigned to the Carrier Transport Squadron of the Pacific Fleet. The carrier departed on 25 July with a load of aircraft, bound for the West Pacific. Transiting via Pearl Harbor, she headed to Majuro, in the Marshall Islands. She returned to the West Coast on 23 August, and following a seventeen-day period at port, she left on 9 September for another transport mission. She steamed to Finschhafen, New Guinea, before proceeding to Manus Island in the Admiralty Islands, where she unloaded her aircraft. There, she took on an air group returning to Pearl Harbor, arriving at Oahu in mid-October.