The 31st Marine Expeditionary Unit was activated on March 1, 1967, as Special Landing Force Alpha, for operations in Vietnam. It made the first of many amphibious deployments from Okinawa to the coast of Vietnam on April 10, 1967. Ten days later, it was committed to Operation Beaver Cafe/Union #1. From May to September, Special Landing Force Alpha was entrusted to ground operations 22 days out of each month.

It was during this period of intense combat that Special Landing Force Alpha earned the Presidential Unit Citation. The unit participated in supporting operations ashore during the following three years, returning to Okinawa periodically for re-outfitting and the rotation of forces.

Special Landing Force Alpha was officially designated as the 31st Marine Amphibious Unit (MAU) on Nov. 24, 1970. Once more the unit returned to the Gulf of Tonkin. This time, however, the 31st MAU would not be committed to overt land operations as the Vietnam War was winding down. The 31st MAU performed presence missions and conducted a series of special operations through May 1971. From June 1971 until April 1975, the 31st MAU conducted numerous deployments to the waters off Vietnam, the last mission conducted during Operation Frequent Wind on April 29. This operation was the final evacuation of Saigon as North Vietnamese forces entered the city.

The 31st MAU remained the forward-deployed U.S. presence in the Western Pacific and Southeast Asia. Combat operations were replaced by regional exercises, which allowed training opportunities in a variety of countries. In 1983, the 31st MAU was recalled from a combined exercise with local forces in Kenya, and positioned in the Mediterranean. Its mission from September to October 1983 was to support U.S. Peacekeeping Forces in Beirut during an intense period of complex political and life-threatening conditions in Lebanon. It was the 31st MAU's last combat operation and the unit was deactivated in May 1985.

The unit was reactivated as the 31st Marine Expeditionary Unit (Special Operations Capable) on Sept. 9, 1992. Since then, the 31st MEU (SOC) has successfully negotiated seven special operations certifications and continues to participate in deployments with Amphibious Squadron 11 throughout the Western Pacific.

Presidential Unit Citation - Vietnam 1967

Navy Unit Commendation - Vietnam 1968

Meritorious Unit Citation - Vietnam 1975; Beirut 1983

National Defense Streamer 1965 - 1975; 1992 - 1996

Vietnam Service Streamer - 2 Silver Stars, 2 Bronze Stars 1967 - 1972

Vietnam Cross Of Gallantry - 1969