The 2nd, 3rd and 4th Engineer Special Brigades were assigned to the Southwest Pacific Area, and participated in the campaigns in the Bismarck Archipelago, New Guinea, Leyte, Luzon, the Southern Philippines and Borneo campaign. The 1st Engineer Special Brigade fought in both theaters of the war, participating in the Okinawa campaign near the end of the war. The 2nd Engineer Special Brigade remained active after the war, and served in the Korean War before being inactivated in 1955.