Marine Scout Bombing Squadron 133 (VMSB-133) was activated on May 1, 1943 at Marine Corps Air Station El Toro, California. After training over the summer they left for Hawaii and arrived at Marine Corps Air Station Ewa on September 9, 1943. From Ewa, the squadron was split into two sections with one heading to Johnston Atoll and the other to Palmyra Atoll for six months of anti-submarine patrols. Following these tours they returned to MCAS Ewa only to leave again on June 25, 1944 heading to Torokina on the island of Bougainville. During October and November 1944 the squadron carried out strikes against targets on Bougainville and New Britain.