In April 1966, the Battalion deployed to the Republic of Vietnam and served there until 1971. During this time, 2d Battalion, 5th Marines participated in combat operations at Huế, Quế Sơn, Phu Bai, Đông Hà and Phú Lộc. Immediately after their return to Camp Pendleton in 1971, the Battalion joined Operation New Arrivals, the relocation of Southeast Asian refugees to the United States.