The history of mail and postage stamps of Thailand covers the development of postal services in the Kingdom of Thailand (Siam), a state in Southeast Asia located on the peninsulas of Indochina and Malacca, with its capital in Bangkok, and includes the pre-stamp period and the stage of further development of the postal service in this country from the beginning of issuing its own postage stamps in 1883 and joining the Universal Postal Union in 1885.