On 1 September 1950, the 40th Infantry Division was again called into active federal service for the Korean War. Shipping out of Oakland and San Francisco, California in late March 1951, the division deployed to Japan for training. For the next nine months, they participated in amphibious, air transportability, and live fire training from Mount Fuji to Sendai. On 23 December, the division received alert orders to move to Korea. The division moved to Korea in January 1952. After additional training, the division moved north in February 1952, where it relieved the 24th Infantry Division on the battle line. At the time the division consisted of the 160th, 223rd, and 224th Infantry Regiments, and smaller non-regiment-sized units.