 Initially part of the 33rd Infantry Division during World War I, the 129th Infantry Regiment was detached on 31 July 1943, sent as the Espiritu Santo garrison force and later attached to the 37th Infantry Division on Bougainville during the Bougainville campaign on 13 November.The 129th Infantry Regiment participated during the Philippines campaign and was detached and attached to the 33rd Infantry Division between 26 March and 10 April 1945, before rejoining the 37th Infantry Division.The regiment is now known as the 129th Regiment (Regional Training Institute), providing training.