After 1945

Royal Marines were involved in the Korean War. 41 (Independent) Commando was reformed in 1950, and was originally envisaged as a raiding force for use against North Korea. It performed this role in partnership with the United States Navy until after the landing of United States Army X Corps at Wonsan. It then joined the 1st Marine Division at Koto-Ri. As Task Force Drysdale with Lt. Col. D.B. Drysdale RM in command, 41 Commando, a USMC company, a US Army company and part of the divisional train fought their way from Koto-Ri to Hagaru after the Chinese had blocked the road to the North. It then took part in the famous withdrawal from Chosin Reservoir. After that, a small amount of raiding followed, before the Marines were withdrawn from the conflict in 1951. It received the Presidential Unit Citation (United States) after the USMC got the regulations modified to allow foreign units to receive the award.

After playing a part in the long-running Malayan Emergency, the next action came in 1956, during the Suez Crisis. Headquarters 3 Commando Brigade, and Nos 40, 42 and 45 Commandos took part in the operation. It marked the first time that a helicopter assault was used operationally to land troops in an amphibious attack. British and French forces defeated the Egyptians, but after pressure from the United States, and French domestic pressure, they backed down.

Further action in the Far East was seen during the Konfrontasi. Nos 40 and 42 Commando went to Borneo at various times to help keep Indonesian forces from causing trouble in border areas. The highest-profile incident of the campaign was a company-strength amphibious assault by Lima Company of 42 Commando at the town of Limbang to rescue hostages.

From 1969 onwards Royal Marine units regularly deployed to Northern Ireland during The Troubles, during the course of which 13 were killed in action. A further eleven died in the 1989 Deal bombing of the Royal Marines School of Music.

The Falklands War provided the backdrop to the next action of the Royal Marines. Argentina invaded the islands in April 1982. A British task force was immediately despatched to recapture them, and given that an amphibious assault would be necessary, the Royal Marines were heavily involved. 3 Commando Brigade was brought to full combat strength, with not only 40, 42 and 45 Commandos, but also the 2nd and 3rd Battalions of the Parachute Regiment attached. The troops were landed at San Carlos Water at the western end of East Falkland, and proceeded to "yomp" across the entire island to the capital, Stanley, which fell on 14 June 1982. Not only was 3 Commando Brigade deployed, but also a Royal Marines divisional headquarters, under Major-General Jeremy Moore, who was commander of British land forces during the war.

The main element of 3 Commando Brigade was not deployed in the 1991 Gulf War except for 24 men from K Company 42 Commando Royal Marines who were deployed as six man teams aboard two Royal Navy frigates and two Royal Navy destroyers. They were used as ship boarding parties and took part in numerous boardings of suspect shipping. The main element of 3 Commando Brigade was deployed to northern Iraq in the aftermath to provide aid to the Kurds, as part of Operation Safe Haven. The remainder of the 1990s saw no major warfighting deployments, other than a divisional headquarters to control land forces during the short NATO intervention that ended the Bosnian War.

More recently Royal Marines detachments have been involved in operations in Kosovo, Sierra Leone, East Timor and the Congo.

From 2000 onwards, the Royal Marines began converting from their traditional light infantry role towards an expanded force protection type role, with the introduction of the Commando 21 concept, leading to the introduction of the Viking, the first armoured vehicle to be operated by the Royal Marines for half a century.

In November 2001, after the seizure of Bagram Air Base by the Special Boat Service, Charlie Company of 40 Commando became the first British regular forces into Afghanistan, using Bagram Air base to support British and US Special Forces Operations. Bravo Company 40 Commando arrived in December 2001, eventually moving into Kabul itself, beginning the building of the infrastructure which became ISAF. 40 Commando continued to roulement Companies until October 2002.

2002 Saw the deployment of 45 Commando Royal Marines to Afghanistan, where contact with enemy forces was expected to be heavy. However little action was seen, with no Al-Qaida or Taliban forces being found or engaged.

3 Commando Brigade deployed on Operation TELIC in early 2003 with the USMC's 15th Marine Expeditionary Unit under command. The Brigade conducted an amphibious assault on the Al-Faw peninsula in Iraq, 42 Commando securing the port of Umm Qasr and 40 Commando conducting a helicopter assault in order to secure the oil installations to assure continued operability of Iraq's export capability. The attack proceeded well, with light casualties. 3 Commando Brigade served as part of the US 1st Marine Division and received the US Presidential Unit Citation.

In late 2006, 3 Commando Brigade relieved 16 Air Assault Brigade in Helmand Province, Afghanistan, as part of Operation Herrick. In 2008, Lance-Corporal Matthew Croucher of 42 Commando was awarded the George Cross (GC) after throwing himself on a grenade to save the lives of the other marines of his patrol. Remarkably, he managed to keep his rucksack and the grenade, and that together with his body armour, meant he suffered only very minor injuries.