Marine Medium Helicopter Squadron 365 was established on July 1, 1963 at Marine Corps Air Facility Santa Ana, California. Flying UH-34Ds, the squadron's mission was to provide assault transport of troops and cargo in support of Fleet Marine Forces during ship-to-shore movements. HMM-365 was reassigned to Marine Corps Air Station Futenma, Okinawa in August 1964 in preparation for the squadron's deployment to the Republic of Vietnam. The squadron arrived at Da Nang Air Base on October 7, 1964 and immediately began performing re-supply missions in support of Operation Shufly.