The attack transport reached Pearl Harbor on 9 January 1945 and disembarked her passengers. The following day, she shifted berths to prepare for her first major operation—the assault on Iwo Jima, a small island in the Volcano Islands chain situated midway between Japan and American B-29 bases in the Marianas. Ideally suited to serve both as a base for fighter escort and as an emergency landing area for B-29's, Iwo Jima also figured prominently in Japanese defense plans. "Barrow" took on board a cargo of 8 inch ammunition to replenish the heavy cruisers supporting the landings. She embarked elements of the 5th Amphibious Corps, both at Pearl Harbor and at Maui, and then conducted four days of intense training at Maalaea Bay at Maui. Afterward, she spent nine days of logistics and rehabilitation at Pearl Harbor.