The Similan Islands are widely regarded as Thailand’s #1 dive site but also one of the best diving locations in the world. There are at least 35 credited dive sites associated with the Similans.

Mu Ko Similan are a group of nine small islands, with National Park status under the care of the Royal Forestry Department, in the Andaman Sea 52 km west of Khao Lak. They are renowned the world over for their natural beauty and incredible underwater scenery.
Besides being blessed with some of the most picturesque white powdery sandy beaches one could ever imagine, with lush scenic flora inland, extremely huge smooth granite boulders have been seemingly carelessly scattered around over the eons to create a truly stunning scene. These same smooth formations cascade and plunge into the azure clear warm waters to form seamounts, rock reefs and , and the Islands’ reputation as a world-class dive site is well deserved.

The word ‘Similan’ is derived from the Malay word “sembilan” meaning nine. Each island has both a name and a number. The Thai’s sometimes refer to them as Ko Gao (or Nine Islands), and even the local fishermen refer to them by number rather than name.
Counting in order from the north, they are: Ko Ba-Ngu (No. 9), Ko Similan (No. 8), Ko Payu (No. 7), Ko Miang Sam (No. 6), Ko Miang Song (No. 5), Ko Miang (No. 4), Ko Payan (No. 3), Ko Payang (No. 2) and Ko Hu Yong (No. 1).
In addition there is a small rock outcrop between number 7 and number 8, known as Hin Pusar or Elephant Head Rock.

Similan Island Marine Life

are world-famous for the incredible diversity of marine life. With fields of blue and yellow soft corals, forest of hard coral, hundreds of species of reef dwellers – Angelfish, Bannerfish, Lionfish, Puffers and more are all right here waiting for you. We also frequently see the “pelagic” or open ocean fish – Sharks, Tuna, Barracuda, and Snappers all swing by. Of course we must point out our real treasures – Manta Rays, Whale Sharks and Turtles.

Surin Island Animal Life

Inland the islands are essentially relatively low lying formations with some thick forest, sheltering rare species like Nicobar pigeon, the hairy-legged mountain land crab, crab-eating monkeys, mangrove monitor lizards, dusky langurs, and flying foxes.

The best months to visit the Similan Islands are from November to May, 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.

Ecosystems, Currents and the Monsoon

Above and below the water there is a marked underwater contrast between the western and eastern sides of the islands. This is due to the weather patterns – especially the monsoons. During the monsoons of June through September the winds, waves and currents come pounding in from the South West. 5 months of pounding weather strongly affect the entire ecosystem.
The currents to the West have kept the huge, soft coral clad, granite boulders exposed, and free of sand, resulting in dramatic formations, peaks, canyons and overhangs descending beyond the depths of recreational diving. These are quite exhilarating dives, and best done by experienced divers. Among the most famous sites is Christmas Point.
Currents on the west side can sometimes be unpredictable, affected not only by tidal action but occasional surges of nutrient-rich water causing planktonic blooms. Not surprisingly, deep-water creatures such as manta rays and whale sharks visit the area at this time of year.
On the Eastern coasts the boulders have remained buried as the fine sandy beaches slope gently down to reveal vast hard coral gardens. Here, the currents are gentle and much easier diving conditions prevail. There is a diverse and prolific mix of fish life, with a colorful abundance of reef species. The best example of this site is East of Eden.

Day Trips are available, as well as Overnight snorkeling Trips! The serious diver will opt for a liveaboard heading for the world-class dive sites.

The islands are uninhabited except for the Park HQ on Ko Miang ( #4) and a small ranger station on Ko Similan ( #8 ), both of which provide basic amenities (camping, restaurant, toilets and showers). There are bungalows on Ko Miang, but they are owned and operated by the Thai government, while nice are not very luxurious. If you wish to stay on the Islands, we are happy to arrange everything – or participate in one of our tours! Advance booking is Strongly advised.