[5] The unit participated in continuing combat operations ashore over the next three years, including the Vietnam Tet counteroffensive in 1969, while returning to Okinawa periodically for re-outfitting and the rotation of forces.

[14] On April 13, the evacuees were flown to U-Tapao Air Base in Thailand and Amphibious Ready Group Alpha proceeded to the South China Sea to rendezvous with Task Force 76 as it stood by to implement Operation Frequent Wind, the evacuation of Saigon.

[15] After departing the Gulf of Thailand, the 31st MAU was attached to the 9th Marine Amphibious Brigade in support of Operation Frequent Wind, the final evacuation of Saigon as North Vietnamese forces entered the city.

On April 24, this group in support of 3/3 Marines rendezvoused with USS Nimitz off the coast of Iran as reserve in the ill-fated Operation Eagle Claw, the failed attempt to rescue of the 53 American captives at the Embassy of the United States, Tehran.

Its mission from September to October 1983 was to support the Multinational U.S. peacekeeping forces in Beirut during an intense period of complex political and life-threatening conditions in Lebanon.

[7] The 31st MEU, in concert with Amphibious Squadron Eleven (PhibRon 11), deployed to support Australian Defence Force (ADF) operations in East Timor from September 30, 1999, through October 26, 1999.

After the September 11 attacks, the MEU received a 96-hour warning order for deployment and was notified that naval shipping was en route to embark them soonest.

The 15th Marine Expeditionary Unit, returning from a deployment to East Timor, was assigned the task of supporting combat operations in Afghanistan.

The 31st MEU then became titled as a Maritime Contingency Force, although it remains capable of conducting the same wide variety of specialized missions on both sea and land.

[22] From May 13 through June 5, 2008, Marines of the 31st MEU sailing aboard the USS Essex's expeditionary strike group waited off the coast of Burma prepared to provide relief as part of Operation Caring Response following Cyclone Nargis.

[25] In October 2010, the 31st MEU conducted humanitarian assistance and disaster relief operations in northern Luzon after Super Typhoon Megi hit the Philippines.

The largest ship, USS Essex (LHD-2), with most of the Marines and Sailors of the 31st MEU aboard, had just completed an exercise in Cambodia and had arrived in Malaysia for a port visit.

The Essex Amphibious Ready Group and the 31st MEU first arrived off the coast of Akita, Japan, 17 March and began flying coastal surveillance flights in the initial stages of Operation Tomodachi.

Working alongside the JGSDF, the 31st MEU delivered 15,000 pounds of supplies to the island and cleared tons of debris from harbors, roads and beaches.

In total, the 31st MEU and the Essex ARG moved 164,000 pounds of relief supplies to those affected by the disaster, including five cities, Oshima Island and the Japanese ship.

The Aviation Combat Element of the 31st MEU, Marine Medium Tiltrotor Squadron 265, flew over 415 flight hours to deliver aid supplies throughout the region.

The rest of the MEU remained at sea in the Leyete Gulf of the Philippines to act as a contingency reserve in the event any more assistance was needed or another disaster were to strike the area.

Over the course of two weeks, the 31st MEU delivered more than 19,000 gallons of water and 47,000 individual meals provided by the Federal Emergency Management Agency to five distribution sites across the island.

From 18–23 April, 31st MEU MV-22B Ospreys operating out of Marine Corps Air Station Iwakuni, Japan, delivered more than 82,000 pounds of food, water, blankets, toiletries and other items to be distributed to earthquake victims.

During Fall Patrol 2018, the 31st MEU and CLB-31 provided assistance to the people of the Commonwealth of the Northern Mariana Islands (CNMI), a U.S. territory, after two devastating typhoons.

[29] During Mangkhut relief efforts, the 31st MEU and CLB-31, partnering with Amphibious Squadron 11, cleared roads and flew 63 air missions to deliver assistance personnel and more than 29,000 pounds of cargo for the people of CNMI.

A more robust follow-on force arrived aboard the USS Ashland on 3 November, aiding with water purification, route clearance, damage assessments and restoration of municipal utilities.