Pattani, town, southern Thailand, on the east coast of the Malay Peninsula. The town is located at the mouth of the Pattani River. Pattani was an independent Muslim city-state, ruling a large portion of the surrounding region until the 16th century, when it became a vassal state of Siam (now Thailand). After 1800 it was divided into seven smaller units, which were incorporated as Siamese provinces in the early 20th century. It has been an international trading port since the 16th century or earlier. Its port facilities export rubber and tin, and it has a small airport. Pop. (2000) 43,690.