Similan Islands Diving Thailand

Similan Islands Diving Thailand

Thailand’s diving in the Similan Islands offers some fantastic variety. The world-renowned Similan and Surin Islands including Richelieu Rock are scheduled in your liveaboard cruise.

Scuba diving holidays to the world-renowned Surin and Similan Islands will also usually include the famous Richelieu Rock.

For the Similan Islands, the underwater topography is unique. Diversity is one of the major factors differentiating this dive area from others worldwide. The underwater scenery on the west and east sides of the islands varies drastically. The dive sites differ significantly as a result depending on the location around the islands themselves.

The name Similan comes from the word 9 because there is a chain of 9 beautiful islands. Crystal clear blue sea and picture-perfect white sandy beaches are the trademarks of the islands. Huge granite boulders are prevalent on the west and tips of the Similan Islands. Whereas the east side is sloping coral reefs with the white sand.

There are more than 20 dive sites in the Similan Islands alone, showcasing this enormous diversity and uniqueness.

Koh Bon and Koh Tachai are included in the Similan Marine Park and often considered part of the area. Richelieu rock and the fantastic underwater life found at this pinnacle is under the protection of the Surin Marine Park.

Take a look at the Liveaboard Cruise options below.

Similan Islands Diving Thailand - 30 LIVEABOARDS

From $5 / day

Sea World 1 Liveaboard in Myanmar

A diver-designed liveaboard offering Scuba Diving in Myanmar and Thailand’s best dive sites.

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From $6 / day

Thai Sea Liveaboard in Myanmar

Join this liveaboard in Myanmar to enjoy the remote site of diving Burma on a budget.

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From $7 / day

Camic Liveaboard in Thailand

Enjoy a scuba diving holiday to the Similan Islands with this budget-friendly option.

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Similan Islands Dive Sites

The main area for the liveaboards is the Similan and Surin marine parks. These parks include the famous Richelieu Rock, Koh Tachai, Koh Bon and the Similan Islands themselves.

Similan Islands Highlights

The Similans is a chain of 9 islands running north-south with many diverse dive sites.

North Point

This boulder site on the north of island number 9 with swim-throughs and a pinnacle in the deep and shallow reef where you can end the dive.

Experienced divers can go out to the 40m pinnacle over a sand channel where the gorgonian fans are in excellent condition.

The main area has many swim throughs and ledges where you can find ornate ghost pipe and many banded pipefish. Leopard sharks can be found sleeping in the sandy channels between the boulders and the occasional white tip reef sharks pass by.

Red fire gobies are in the sandy are with mantis shrimps. As you head to the shallow staghorn reef look for barracuda and hawksbill turtles.

Three Trees

Located on the east side of island nine is a sloping reef dive with some boulder formations in the deeper area. Named after the distinctive three trees that stand out from the island’s jungle this is a drift dive that can offer some great marine life. Batfish school in the shallow waters along with 1m milk fish hanging still. The site is home to many leopard sharks with occasional sightings of reef sharks, shovelnose rays and manta rays.

Elephant Head

Often called the most unique dive in the area Elephant Head or Hin Pusa is a rocky granite outcrop between islands 7 and 8. One of the boulders breaking the surface gave the dive site its name.

The site itself is a collection of boulders stakes and resting on each other forming a maze of swim throughs over the whole area. Some of the ledges are home to white tip reef sharks sleeping during the day until disturbed. Look out for the egg cowries on the boulders with the black mantles over the pure white shell and the red fire gobies darting in and out of the sand.

Circling the dive site are the huge black trevally and occasional large pelagics like manta rays.

West of Eden

A boulder site on the west side of island 7, this deeper site with a coral rubble substrate that is home to mantis shrimps and juvenile rock mover wrasse.

Sea snakes and turtles are regular visitors to the site and khules stingrays can be found in the sand beyond the rubble. The granite boulders have gorgonian sea fans, table corals also covering their surface where inside you can see the coral crabs hiding, in the crevices look for Durban dancing shrimp.

There is a large coral bommie part way down the site which is home to a giant frogfish ideal for photographers.

East of Eden

On the opposite side of island 7 and by contrast is a reef dive. The turquoise water descends from a 5m self to 30m. The hard coral reef has staghorn, brain corals, lettuce and whip corals and giant gorgonian sea fans, hovering above this are Moorish idols, butterfly fish, lionfish and schools of snappers. Near the end of the dive, there is a large coral bommie that is one of the most photographed areas in the marine park. Macro life of shrimps, pipefish, coral crabs and nudibranchs are here. Past this area is a Japanese garden area with leather and fire corals where hawksbills turtles are often seen.

Anita’s Reef

Located between islands 5 and 6 is usually a check-out dive but offers some great diving. A patch reef with white sand that’s home to fields of garden eels, khules stingrays and purple fire gobies.

There is a substantial coral block part way down the reef with large gorgonian fans and anemones that is teaming with glassfish and home to the rare longnose hawkfish. Along the reef look for the banded sea snakes, clown triggerfish and the many bluefin trevallies.

Koh Bon

Koh Bon has two dive sites, the west ridge and the pinnacle.

The west ridge is the most popular as it is a cleaning station for Manta rays which are regularly spotted here during the season in numbers. The ridge starts from the bay where a steep wall covered in soft coral depends down underwater in steps. Whip corals begin to appear as the protection of the island disappears. Around the ridge area or the surrounding reef, Manta Rays are often seen gliding in the currents and being cleaned.

The pinnacle dive site is away from the island and needs a free decent as no mooring line is attached. Divers should be experienced to be able to complete this dive as a quick descent to the small site is needed. You are rewarded with big gorgonian sea fans and leopard sharks once you reach the site itself.

Koh Tachai

There are several sites on this northernmost island of the Similan marine park, the most popular being the plateau on the southern tip.

A decent on the line is needed when currents are running to the plateau that starts at 14m, the top encrusted with hard coral. Manta rays and whale sharks are often found here enjoying the currents that bring rich nutrients to the area. Batfish school around the mooring line and chevron barracuda close by. The boulder formations have schools of snappers and fusiliers swimming around them, and leopard sharks are in the deeper areas resting on the sand.

Surin Marine Park Highlights

Together with the Similan Islands 100km to the south, the Surin Islands are one of the most famous diving and marine life viewing sites in the world.

Richelieu Rock

Richelieu Rock is the most famous site in Thailand and was discovered by Jacques-Yves Cousteau. It descends from the surface past 40m, and its horseshoe shape is host to a multitude of marine life. The walls of the pinnacle have tree corals, sea fans, sea whips and encrusting corals all over it.

Chevron barracuda school around the mooring line and the giant barracuda can often are in solitude around the site.

Cuttlefish and octopus are over the reef and seabed with stingrays and occasional eagle rays.

Large pelagic life is regularly spotted from January to April with manta rays and whale sharks circling the pinnacle.

Macro life here is impressive with ornate ghost pipefish, tiger tail seahorses, many banded pipefish, crabs, squat lobsters, nudibranchs and a few pairs of harlequin shrimps.

The Surin Islands

The Surin Islands themselves are the closest land to Richelieu Rock but the sites are mostly closed in this area, and snorkelling only is permitted.

Koh Torinla is used for night dives by some vessels.

Boonsung Wreck

Located about 1 hour from the port of Thab Lamu used by many of the liveaboards visiting the north Andaman are two wrecks that can be included on the final day.

The Boonsung wreck is the most popular as it is sat in about 20m of sand and hosts an extensive range of marine life in a small area.

The old tin mining platform wreck was scuttled in 1984, as it has no reef in the immediate area, it became a host to a multitude of species over the next years.

The wreck itself was whole until the tsunami in 2004 which ripped it apart and scattered the top portion into the sand. This actually improved the site as it became a larger area, the wreck itself is covered in clams and oysters and has many nudibranchs covering the surface.

There are honeycomb and zebra morays in most of the holes in the structure. The cross area has stonefish buried in the sand along with frogfish and seahorses. Under the wreck look for blotched fantail rays and marble groupers and in the sandy bottom the goby and partner shrimp along with spearing mantis shrimps.

Schools of snappers, barracuda and fusiliers surround the wreck and many porcupine fish circle the structure.

Other Activities

The marine parks have ranger stations on #3 in the Similan Islands, plus one on Koh Tachai and one in Surin.

The station on the Similan island #1 is off limits to tourists and visitors as it homes a turtle project and hatchery.

Islands #4 and #8 host the ranger stations for the staff who patrol the park along with some limited tent or basic bungalow accommodation. There is a restaurant on both islands with a limited choice as all ingredients need to be brought from the mainland.

Both of these islands also have a viewpoint to view either the north or south part of the islands. #8 viewpoint is pretty easy to reach and has a purpose built walkway, but island four you will need to be prepared for a hike and some rope climbs. An easier option is to walk from one beach to the other via the jungle path that has been cleared.

The Similans are home to many bird species lizards and fruit bats.

Koh Tachai marine park station is located on the white sand beach but not very accessible due to the shallow corals situated in front of this area.

Koh Surin ranger station is located on Koh Surin Nuea and has both bungalows and tents available for rent and a visitor centre and restaurant.

Jungle and beach walks start from this area.

Marine Park and Conservation in Similan Islands

Located 70km off the coast of Thailand, Koh Similan means nine islands in Malay and Thai. The name covers the first 9 islands under the park protection when founded in 1982, in 1998 the islands of Koh Bon and Koh Tachai were also added to the park area increasing the size to around 140 km2.

Each Island has a name and number for ease of reference. From North to south they are.

Island 11:     Koh Tachai

Island 10:     Koh Bon, also known as Koh Talu

Island 9:       Koh Ba-Ngu, also known as Koh Bayu

Island 8:       Koh Similan

Island 7:       Koh Hin Pousar

Island 6:       Koh Payu, also known as Koh Pa Yu

Island 5:       Koh Ha

Island 4:       Koh Miang, also known as Koh Meang.

Island 3:       Koh Payan, also known as Koh Pa Yan

Island 2:       Koh Payang, also known as Koh Pa Yang

Island 1:       Koh Huyong, also known as Koh Hu Yong

The park offers clear water with white sand beaches and is considered to be one of the best diving sites in the world.

Any vessel entering the park has to follow the rules imposed and controlled by the park officials, this includes no anchor use only mooring buoys, and the use closed wastewater systems to avoid any pollution.

A few years ago the islands came to the attention of the Thai Royal Family ensuring the continued protection of these islands; the princess even has a cabin here.

The diving can only take place at islands 4-9, as the islands 1-3 are closed to activities due to a long-running conservation project.

Further north again in Surin National Park is a pinnacle called Richelieu Rock, this is the best dive site in Thailand. Established in 1981 the marine park consists of five islands covering 141km2 situated 55km off the coast close to the border with Myanmar.

Koh Surin Tai, Koh Ri, Koh Khai and Koh Klang along with Richelieu Rock are the other land masses in the park.

Surin Islands are populated unlike Similan and have two ethnic Moken communities known locally as ”Chao Lay”.

Mokens are nomadic sea people who number around 150; they are hunters and gatherers residing in the Mergui Archipelago. Most of their time out at sea and moor in sheltered locations during the monsoon season.

Except for the villages and campsites, the majority of the land area of the islands are off limits to the visitors.