Thailand is located in Southeast Asia on the Indochina Peninsula.

An excerpt from the article 31 facts about Thailand

It lies between the Indian Ocean and the Pacific Ocean. From the west, it is surrounded by the Andaman Sea (a coastal sea located in the north-eastern part of the Indian Ocean), and from the east and south by the waters of the Gulf of Thailand (formerly called the Gulf of Siam, in the western part of the Pacific Ocean).