The RMR can trace their roots back to the Royal Marines Forces Volunteer Reserve (RMFVR) formed in the City of London under the Royal Marines Act 1948. The RMFVR were officially formed on the 5th November 1948 at a ceremonial parade on Bunhill Fields, the same place the Royal Marines were formed on 28th October 1664.

In the beginning, Reservists were chiefly former hostilities only (HO) personnel. They were mainly, but not solely, Royal Marines who had gained experience in WWII and trained in order to support the Corps against the threat from the Soviet Bloc. However, today the majority of Reservists have no previous military experience. Their transition from civilian to Marine, is therefore more challenging. Moreover, 21st century threats compel the training to be more comprehensive to equip the Marine with an arsenal of skills to face any eventuality. The RMR have adapted to these changes and remains flexible, continuing to train in order to support properly the Corps that Sir Winston Churchill described as "The finest in the world".