Satun is one of the southern provinces of Thailand. Neighboring provinces are (from north clockwise) Trang, Phatthalung and Songkhla. To the south it borders Perlis of Malaysia. The name Satun is a Thai corruption of its original Malay name, Setul (santol, or wild mangosteen tree).
The province is located on the Malay Peninsula, on the shore of the Andaman Sea. It is separated from Songkhla Province by the Nakhon Si Thammarat mountain range, and from Malaysia by the Sankalakhiri mountains.
The Ko Tarutao and Ko Phetra marine national parks are part of the province. Close to the border with Malaysia is the Thale Ban National Park, a big freshwater swamp area.