The Royal Thai Marine Corps or RTMC are the marines of the Royal Thai Navy. The Royal Thai Marine Corps was founded in 1932, when the first battalion was formed with the assistance of the United States Marine Corps. It was expanded to a regiment in 1940 and was in action against communist guerrillas throughout the 1950s and 1960s. During the 1960s the United States Marine Corps assisted in its expansion into a brigade. The Royal Thai Marine Corps saw action on the Malaysian border in the 1970s, and has now been increased to four brigades.

The Royal Thai Navy is the naval warfare force of Thailand. Established in 1906, it was modernised by the Admiral Prince Abhakara Kiartiwongse (1880–1923) who is known as the father of the Royal Navy. It has a structure that includes the naval fleet, Royal Thai Marine Corps, and Air and Coastal Defence Command. The RTN headquarters is at Sattahip Naval Base.