Thailand at the SEA Games

Thailand started sending athletes to the Southeast Asian Games in 1959 as a founding member of the Southeast Asian Games Federation (SEAGF) alongside Burma (now Myanmar), Kampuchea (now Cambodia), Laos, Malaya (now Malaysia), and the Republic of Vietnam (South Vietnam). Thailand first competed in the Southeast Asian Peninsular Games (SEAPG) from its namesake of "Peninsular" meaning the peninsular nations of Southeast Asia would be competing in the said games.

Source: Wikipedia — Thailand at the SEA Games (CC BY-SA 4.0)