After being commissioned, "Bismarck Sea" engaged in training exercises off the West Coast throughout June. On 1 July, she left San Pedro ferrying aircraft and pilots to Pearl Harbor. After unloading her aircraft, she loaded more aircraft and ferried them to the Marshall Islands, arriving at Majuro Atoll on 16 July. She then proceeded back to Pearl Harbor, carrying damaged aircraft, arriving on 29 July, along with her sister ship . Throughout August, she was stationed at San Diego for a four-week overhaul, where she received her combat air contingent, Composite Squadron (VC) 86. Between 7 September, and 16 October, she engaged in additional training exercises. She then steamed to Ulithi, Caroline Islands, to join Admiral Thomas C. Kinkaid's 7th Fleet on 1 November. Between 14 and 23 November, she operated off Leyte and Mindanao in support of operations onboard Leyte. On 21 November, a Japanese aircraft made a strafing run along the carrier, but without inflicting any damage, and escaped to the northwest before it could be engaged.