Dive Sites of Similans Islands

Scuba Diving Similans

Similans Islands Best Dive Sites

Located approximately 100 km north-west of Phuket the world-famous Similan National Marine Park consists of a group of nine islands. In fact the name Similan comes from the Malay word for nine, "sembilan". Renowned throughout the world this place has it all: pure white sandy beaches, lush tropical vegetation and most importantly absolutely fantastic diving. The superb underwater visibility combined with the great number and variety of dive sites is a wonder to behold.

For five months of the year (mid-May to mid-October) the Similan Islands become inaccessible to scuba divers due to heavy monsoons. What this has created are two completely different sets of topography for each island. On the east sides, protected from the monsoons, are gentle sloping hard coral reefs whilst on the west sides which are exposed to the high winds and waves, are fantastic boulders covered in soft corals and sea fans. When you add the rich diversity of aquatic life and the fact that it is a protected marine park...well you just have to experience it to believe it. Whale sharks, manta rays, turtles, sea horses, pipefish, frogfish, whitetip reef sharks, leopard sharks....the list is endless.

Similans Islands

Consisting of nine islands the Similan islands has a multitude of dive sites offering a fantastic variety of marine life from large sharks to miniscule nudibranchs. Below are descriptions of some of our favourite Similan sites.

Beacon Reef (Island #8)

Beacon Reef is a reef consisting almost entirely of a large variety of hard corals. The reef itself slopes very gently to a depth of about 6 metres where the reef suddenly slopes and drops down to a sandy bottom reaching depths of 30 metres. Currents range from mild to medium. A large variety of reef fish are present including a number of giant moray eels. Look out for the Atlantis 2000, the wreck of a diving boat that got a little bit too close to the island a few years back. Look into the blue for tuna, jacks and possibly even a passing eagle ray.

Christmas Point (Island #9)

Christmas Point consists of a large series of boulders spread over a wide area to depths of 30 metres. If you like swim-throughs then this is a must. Negotiate your way in between the boulders and arches and enjoy the wonderful variety of soft corals and sea fans as you go. A good chance to see a white tip reef shark or leopard sharks plus possibly even turtles. Watch out for the currents. Ranging from mild to strong they can change at any moment!

Elephant Head (Island #8)

Elephant Head consists of a series of large boulders of which a few actually break the surface, one of which is said to resemble the head of an elephant (hence the name). A great dive site with wonderful soft corals and fans plus a number of swim-throughs. It's deep too, reaching depths of 40 metres or more. Currents range from mild to strong and often change direction as they rebound off the rocks. There is the possibility of sharks and turtles as well as large schools of snapper and other common reef fish. Keep looking around as both manta rays and whale sharks have been known to frequent this area.

Shark Fin Reef (Island #3)

Shark Fin reef consists of a large series of boulders running in a north-south direction. Descending to depths of 30 metres to a sandy bottom the boulder ridge sometimes drops straight down, in other places leveling off shallower to form small plateaus. A great site for drift dives with currents ranging from mild to strong. Just let yourself go with the flow and expect to see all the common reef fish including a multitude of banner fish plus the rare and beautiful clown triggerfish. Other highlights include Napoleon wrasse, leopard sharks and even the occasional manta ray.

Koh Bon and Koh Tachai

To the north of Koh Similan islands are two further islands, namely Koh Bon and Koh Tachai. These islands each have spectacular dive sites to rival anything in the Similans. Consider also the fact that these are definitely the two most likely places to encounter manta rays and possibly even a whale shark, it all adds up to each being a "must visit" destination. In fact, Koh Bon itself can even be visited by day trip from Phuket!

Koh Bon

North of the Koh Similan Islands, Koh Bon island has a number of dive sites ranging from coral gardens to boulders to the challenging but spectacular Koh Bon pinnacle. With depths of 40 metres plus you can make dives here as deep or as shallow as you wish but can guarantee it will be full of surprises. Bearded scorpion fish and frog fish can be found in the bay areas as can octopus, cuttlefish, turtles and both blacktip and whitetip reef sharks. Out in the blue are tuna and trevally, barracuda and jacks.

Keep your eyes open because somewhere out there could be a manta ray, the most graceful underwater creature you can see. With wing-spans sometimes in excess of five metres they are a spectacular thing to behold! Koh Bon is famous for these and they can be in the bays or in the blue so you really need eyes in the back of your head. Let their curiosity work to your advantage. Stay still and don't be surprised if they circle around time and time again. Currents are variable depending which part of the island you dive at and at what time.

Koh Tachai

Located even further north of the Similans than Koh Bon, Koh Tachai island offers excellent but sometimes challenging diving. The main area to dive is a site called "The Dome" that consists of a large rock plateau starting at depths of about 13 metres and dropping down as deep as 35 metres. There are a fantastic collection of hard corals, soft corals and sea fans forming some spectacular underwater scenery. The reef itself is also covered in a multitude of snappers, fusiliers, triggerfish, batfish and other reef fish giving a profusion of colour.

On the edges where the reef meets the sand leopard sharks can be seen resting in the day time. Many open ocean visitors also pass through these waters. This area is one of the most well known places in Thailand for manta rays and even the occasional whale shark so keep a close lookout. Watch out for the currents. Although sometimes mild they can also be very, very strong.

Richelieu Rock

Richelieu rock is often sited as the best dive site in Thailand and one of the best in the world. Once you've dived it you'll understand why it has such a deserved reputation. It's not just the whale shark sightings most often made between January and April that gives it this reputation but the amazing general diversity of marine life. From big to small plus an amazing array of colours it really is a diver's paradise.

Richelieu Rock lies a long way north of the Similan Islands and close to the Surin Islands. Due to weather conditions it can only be visited between November and April and, even during those periods waves can make visits impossible. All you can see of it from the surface is a small rock just protruding above the water, and only then at low tide. At high tide the rock is often completely hidden. The name itself alledgedly comes from the captain of a warship in the second world war who accidentally crashed into the rock whilst on a mission. If true, then thank goodness because trying to find this site without GPS coordinates would be like finding a needle in a hay stack!

Colour Mad

Richelieu Rock consists of a series of underwater limestone formations of which the main pinnacle can be seen breaking the surface at low tide. The rocks themselves are covered in the most beautifully coloured soft corals, sea anemones, sponges and fans that it is possible to imagine. When the sun is shining and the sea is blue the colours are breathtaking especially with the profusion of tiny colourful reef fish in the shallows with light reflecting off of their scales.

Something For Everyone

Besides the colour, no matter what you are interested in, big or small, you will almost certainly leave more than satisfied. For the lovers of large species you have large groupers, nurse sharks, turtles and leopard sharks. A few metres away from the main pinnacle and about five metres deep are schools of large black fin barracuda circling around. On a good day a manta ray may pass by often gliding by close to the main pinnacle itself as it filters plankton out of the water.

Macro Heaven

For macro lovers this is heaven. This dive site is a mass cleaning station so expect to see a large variety of shrimps possibly including the very rare and beautiful harlequin shrimps. A few different pairs have been resident there for a number of seasons now. Pipefish are abundant from the stunning ornate ghost pipefish to banded and cleaner pipefish. Frog fish are definitely present including the giant frog fish. You just have to find them superbly camouflaged in some crack or crevice. And then there are the resident seahorses!

Whale Sharks

So far we have hardly even mentioned the thing that Richelieu Rock is most famous for, whale sharks. From January to April these gentle giants of the ocean can sometimes be seen cruising by close to the main pinnacle. With their gigantic mouths open as they sift plankton out of the water they are truly a majestic sight to behold. It's just a case of being in the right place at the right time, as simple as that!


The list of possibles and probables can go on and on. One thing is certain. If you don't like this dive site then it's time to go see your doctor. This may be the best dive site you will ever experience!