The Royal Thai Navy or RTN is the naval force of Thailand and part of the Royal Thai Armed Forces. It was established in the late-19th century. Similar to the organisational structure of the United States, the Royal Thai Navy includes the naval fleet and the Royal Thai Marine Corps. The Royal Thai Navy operates out of Sattahip Naval Base in Sattahip Bay. Thailand is the only Southeast Asian country that operates an aircraft carrier, though it is used as a pure helicopter carrier with the retirement of the Harrier fighter wing. Thailand was the second Asian nation to acquire submarines, following Japan, but has had no submarines since 1950.
The United States Navy and Royal Thai Navy conduct the annual joint operation Cooperation Afloat Readiness and Training (CARAT). CARAT is an annual series of bilateral maritime training exercises of the US Navy and the armed forces of Singapore, Thailand, Malaysia, Indonesia, Brunei, and Philippines.