VMF-123 was commissioned on September 7, 1942 at Camp Kearney. The squadron took delivery of 18 Grumman F4F Wildcats in December of that year. A large percentage of the squadron’s initial pilots came from the experienced VMF-121 hoping it would require them less time to become combat ready. The squadron embarked upon the USS Lurline and departed the United States on January 8, 1943. They arrived at Noumea on January 22, where they transferred to the USS Hunter Liggett (APA-14). Arriving at Efate on January 26, they eventually boarded DC-3s flying for Espiritu Santo on February 2. The squadron arrived at Henderson Field on Guadalcanal on February 3, 1943 and flew their first combat mission the following day. Because they were the last of the Marine fighter squadrons to arrive in the Solomon Islands, VMF-123 was the last of these eight squadrons to transition from the Grumman F4F Wildcat to the Vought F4U Corsair.