The Similan Islands
Thailand’s premiere diving destination
Koh Similan (Similan Islands) is widely regarded as Thailand’s best dive destination and one of the world’s top ten dive destinations.
The Similan Islands marine park is an archipelago of nine granite islands in Thailand’s Andaman Sea, about 100 km (60 miles) north west of Phuket. The islands are uninhabited apart from a few national park bungalows and tents. The Similan Islands can only be visit for seven months of the year.
Similan Islands season
The marine park is open from mid October to mid May each year and during those months liveaboards and day trips take divers and snorkelers to experience the crystal clear water and exquisite marine life. The absolute best months to dive the Similan Islands are late January to mid April. From May 15th to Oct 14th the Similan Islands marine park is closed and off limits to all boats.
How to get to the Similan Islands
Most boats departs from Thap Lamu pier (south of Khao Lak in Phang Nga province). The journey is 67 kilometres. Thap Lamu is about 90 minutes drive north of Phuket, we provided land transfers from Phuket.
Similan Islands dive sites
There are two distinct types of dive at the Similan Islands.
The dive sites on the east sides of the islands feature gently sloping coral reefs of hard and soft corals, starting shallow and sloping down to the white sandy bottom at 30-40 metres depth. Large coral bommies are completely covered with soft corals, sponges and sea fans, some big enough to consume a whole dive time.
Schools of tropical fish are everywhere and the fish in the Similan islands are bigger than in other Thailand dive sites. They also seem less afraid of divers and won’t swim away quite as quickly when you point your camera lens in their direction.
These east side dive sites are relatively easy dives with gentle currents to drift along with and very clear water.
Dive sites on the west sides, as well as the north and south tips of the islands offer a different type of diving which is more challenging. They are deeper and currents can be strong. The incredibly clear blue water can trick divers into going deeper than planned.
Huge granite boulders lie piled on top of each other, forming stunning seascapes and creating swim-thru’s, tunnels and caverns. Huge gorgonian seafans grip to the edge of the boulders, swaying in the currents. Soft corals grow around the boulders. Pelagic fish frequent the west coast Similan dive sites including manta rays and occasional whalesharks. Black tip reef sharks can be seen deep. Turtles are pretty common.
Similan Islands beaches
The Similan Islands has some of Thailand’s best beaches, with the whitest sand. Diving day trips from Phuket do not have time to go on the beaches. Most liveaboards include beach excursions. There are viewpoints on Koh Similan (Island #8) and Koh Miang (Island #4).
Similan Islands accommodation
There are national park tents and a few bungalows on Koh Miang (island #4).
The camping should be booked as part of a package that includes speedboat transfers, all meals and snorkeling excursions.
The bungalows are booked through the national parks department, either in Thap lamu or on their website but we’ve found that very difficult to do in practice.
Similan Island names
Similan Island 1 = Koh Huyong
Similan Island 2 = Koh Payang
Similan Island 3 = Koh Payan
Similan Island 4 = Koh Miang
Similan Island 5 = Koh Ha
Similan Island 6 = Koh Payu
Similan Island 7 = Koh Hin Pousar
Similan Island 8 = Koh Similan
Similan Island 9 = Koh Bangu
The islands of Koh Bon and Koh Tachai are north of the Similan islands proper but still part of the Similan Islands marine park (so you have to pay the park fee if you go there).
They offer superb diving with a good chance of seeing manta rays and whale sharks.
Similan Islands temperature on land and underwater
Hot, humid and sunny tropical climate. February to May are usually the hottest months. October is usually the wettest month. November and December are cooler when there is more breeze.
Water Temperature averages of 27°C year round though can go up to 29°C and occasionally drops to 24°C.
What thickness wetsuit for diving the Similan Islands?
A 3 mm shorty wetsuit is sufficient for most people, and that’s what rental wetsuits are. Many divers choose to dive with no wetsuit or just a lycra rashvest / skin suit.
Underwater visibility at the Similan Islands
The Similan Islands has the best visibility of any dive site in Thailand, often in excess of 40 metres. Koh Bon and Koh Tachai to the north can have lower visibility.