With a call en route at Saipan, she arrived off Iwo Jima to land troops and equipment in the invasion of the bitterly contested island 19 February.

She remained off the island to support the hard-fighting Marines until 2 March, when she retired carrying casualties whom she took to Saipan.

Carteret then sailed on to Tulagi and Espiritu Santo, arriving 19 March to load troops and vehicles designated as reinforcements for Okinawa.

Carteret called at Pearl Harbor, Okinawa, and Leyte, where she embarked occupation troops for Jinsen, Korea.

After special training at Pearl Harbor, Carteret was transferred to JTF-1 for use in the atomic bomb experiments at Bikini Atoll, known as Operation Crossroads, between 28 May and 27 August.