During July and August 1944 Bismarck Sea escorted convoys between San Diego, California, and the Marshall Islands. After repairs and additional training at San Diego, she steamed to Ulithi, Caroline Islands, to join the 7th Fleet. During 14 November–23 November 1944 she operated off Leyte in support of the operations and later took part in the Lingayen Gulf landings (9 January–18 January 1945). On 16 February she arrived off Iwo Jima to support the invasion.
On 21 February 1945, despite heavy gunfire, two Japanese suicide planes hit the Bismarck Sea, first on the starboard side under the first 40 mm gun (aft), crashing through the hangar deck and striking the ship's magazines. The fire was nearly under control when the second plane struck the aft elevator shaft, exploding on impact and destroying the fire fighting salt water distribution system, thus preventing any further damage control. Shortly after, the order was given to abandon ship. She sank with the loss of 318 men. Three destroyers and three destroyer escorts rescued survivors over the next 12 hours, between them saving a total of 605 officers and men from her crew of 923. Survivors were then transferred to the transports and .
According to the Dictionary of American Naval Fighting Ships, the destroyer escort directed the rescue operations of the remaining hands, saving 378 of the carrier's crew including the commanding officer, in spite of darkness, heavy seas and continuing air attacks. Thirty of Edmonds' own crew went over the side to bring the wounded and exhausted carrier men to safety.
Bismarck Sea received three battle stars for her World War II operations.