Marine Fighter Attack Squadron 333 (VMFA-333) originally was activated on 1 October 1943 at Marine Corps Air Station Cherry Point, North Carolina, as Marine Scout Bombing Squadron 333 (VMSB-333). The Shamrocks, initially equipped with SBD-4 Dauntless five bombers, later upgraded to SBD-5 versions. The squadron trained in antisubmarine warfare at Boca Chica, Florida, before transferring to Midway Island in July 1944.
At Midway, VMSB-333 stood lonely garrison duty and conducted antisubmarine patrols. In October 1944, the Shamrocks moved to Ewa Field in Hawaii, switched to F4U-1D Corsairs, and became Marine Bomber Fighter Squadron 222 (VMBF-333). The squadron reverted to the VMSB-333 designation in December 1944, and was deactivated on 1 November 1945, never firing in anger at the Japanese.