The southern region covers an area of 13.78% of the country.
The ranges are flanked on both sides by long and narrow coastal plains.
The coast of the Gulf of Thailand is watered by the Tapi, the Chumphon, the park Phanang, the Pattani and the Ko-Lok, while the Andaman coast is rugged and much indented.
On this coastal side, there is no long river expect the Kraburi in Ranong Province.
The southern region is located in the peninsula, forming part of the Malay Peninsula.