Her Majesty the Queen has approved alliances with:

The Royal New South Wales Regiment
and The 1st Commando Regiment of Australia
The Barbados Defence Force.

The Royal Marines have particular associations with:
The Royal Netherlands Marine Corps
The United States Marine Corps
The Princess of Wales's Royal Regiment (Queen's and Royal
Hampshires)
The Argyll and Sutherland Highlanders

In 1995 3 Commando Brigade RM was twinned with The French 9e
Division Infanterie de Marine