Situated in Tambon Ko Phra Thong and covering an area of 350 sq km, Mu Ko Surin is an archipelago of 5 islands: Ko Surin Nuea, Ko Surin Tai, Ko Ri, Ko Khai, and Ko Klang. It was declared a national park on July 9, 1981.
The archipelago is located in the Andaman Sea, near the Thai-Burmese sea border, to the west coast of Thailand. There are beautiful and unspoilt coral reefs, making this area a heaven for diving and snorkelling. Ko Surin Nuea has several bays. The most well-known bay is Ao Mae Yai, the largest bay that offers calm waters. To the southeast of Ko Surin Nuea lies Ao Luek, which is so deep that the sea appears dark green, offering splendid shallow corals as well as sea weeds, sea flowers, coral lines, and various species of fish. Ao Chak is situated to the north of Ko Surin Nuea. The bay possesses unspoilt coral reefs.
Interesting attractions on Ko Surin Tai include Ao Tao, situated to the east of the island. The bay is home to numerous sea turtles and magnificent coral reefs. And Ao Phakkat, situated to the south of Ko Surin Tai, where unspoilt coral reefs can be seen. Ko Klang or Ko Pachumba has a scenic bay called Ao Mangkon. The bay is teeming with splendid coral reefs and many schools of various kinds of fish. And Ko Khai or Ko Torilla situated to the south of Ko Surin Tai.
On the eastern side of the island there is a long stretch of unspoilt and picturesque coral reef. Snorkelling is the most recommended activity here. The full Surin archipelago, as opposed to the marine park, also includes Ko Tachai and Ko Bon to the south, and Richelieu Rock, an isolated limestone pinnacle 18km to the east; these three sites provide fields of psychedelic multilevel coral reefs, plunging vertical walls and underwater pinnacles, and are all truly excellent diving locations for the intermediate and experienced diver.
Off the Surin western shores are submerged pinnacles which are reminiscent of some of the boulder formations of the Similans, but the eastern coast exhibits the best developed reefs. The coral and environs provide habitat to over 800 species of fish such as puffer fish, lion fish, butterfly fish, angel fish, barracuda, sailfish, rock lobsters and other crustaceans, and Moray eels to name just a few. Four species of turtle (the Leatherback, the Green, the Olive Ridley and the Hawksbill) are to be found (try Ao Tau on the south island). And stranger species such as the frog fish and ghost pipe fish have also been sighted around the waters of Ko Surin. Ocasionally whale sharks have been encountered in this area.
The best months to visit the Surin Islands are from December to April, when the weather is dry and pleasant, and the seas are calm. March is the hottest month with temperatures reaching a maximum of 34 C. September is usually the wettest month, and November the coolest (24 C). In fact the Park currently closes from mid-May to mid-November due to the rough seas caused by the southwest monsoon.