The regiment departed San Francisco on 23 March 1944 and arrived in Hawaii on 1 April. The 307th first saw combat during the liberation of Guam in July, 1944. The 307th served in the liberation of the Philippines, arriving on 23 November 1944. The 2nd Battalion was detached for duty on Samar from 30 November until 14 December. The regiment assaulted Yakabi Shima on 26 March and Company G assaulted Kuba Shima on 27 March. The regiment fought on Okinawa from 27 April though 27 June. Arrived in Japan for occupation duties on 5 October 1945 and inactivated there 15 March 1946.