In November 1943 the 2d Defense Battalion was assigned to the V Amphibious Corps for the Battle of Tarawa. They came ashore on November 23 after most of the battle was complete in order to garrison the island against Japanese counterattack from the air. For this operation the battalion was reinforced by one half of the 2d Airdrome Battalion which came in from the Ellice Islands. Following operations at Tarawa the battalion was moved to Hawaii.