"Indiana" entered service in April 1942, by which time the United States was engaged in World War II, and the ship was immediately pressed into action in the Pacific War against Japan. Her first combat came in late 1942 when she supported marines fighting during the Guadalcanal campaign. Over the next three years, she was occupied with two primary roles: naval gunfire support for amphibious assaults across the Pacific and anti-aircraft defense for the fast carrier task force. She shelled Japanese positions during the Battle of Tarawa in November 1943 and the Battle of Kwajalein in February 1944. During the latter operation, she collided with the battleship and was forced to withdraw for repairs.