Designated a national park in 1982 and described by National Geographic as one of the best dive locations in the world, the Similan Islands consists of nine tropical islands in the Andaman Sea. Numerous dive sites can be explored: some are best for experienced divers, others are perfect for all levels. Highlights include stunning scenery, beautiful beaches, spectacular coral growths and amazing submarine rock formations. Accommodation is limited to simple bungalows operated by the national park.
The nine Similans Islands are located about 50 Kilometers west of Khao Lak in southwestern Thailand and can be reached by speed boat in about 90 minutes. The diversity of dive sites is a strong point of the Similan Islands: each site offers its own unique terrain, with features including huge underwater rock pinnacles, thriving hard and soft coral garden reefs, enormous boulder formations and swim-throughs. The marine world of the Similan Islands provides a wealth of subjects for keen photographers.
For beginners, the Similan Islands is a superb diving destination. Many of the sites offer easy diving conditions, amazingly clear water and the chance to spot turtles, anemonefish, moray eels, stingrays, pufferfish, lionfish, batfish and sometimes larger fish such as barracuda and trevally. Giant manta rays can also occasionally be seen. For more experienced divers, the Similan Islands offer notable sites such as Elephant Head Rock, Christmas Point and West of Eden (see below).
Over the last few years much has been written about marine conditions at the Similan Islands. The tsunami of 2004 and Southeast Asian coral bleaching of 2010 have both taken their toll, leaving some areas in a depressing state. The Similan Islands, long considered one of the world's top ten dive destinations, are no longer the pristine, underwater paradise they once were. Unregulated commercial fishing has also had a negative impact on the local environment and there has been a noticeable drop in shark and manta ray sightings. In spite of this, divers who are well informed and know what to expect can still enjoy a great diving experience. Another point to note is that many of the island's attractions and dive sites are often quite crowded. As one of Thailand's top destinations, this is understandable. Do not expect to be alone! Use the menu below to read about each of the dive sites.
The topography of this wonderful dive site is a cluster of huge granite boulders scattered north of island 9, Ko Bangu. To the east and west of the central boulders are smaller rocks in 10-20 meter deep water, and out to the northwest there is another group of very large boulders at 25-30 meters. The site is best for divers at intermediate to advanced levels.
The corals are healthy, but while there is less color here than at other dive sites, the deep, exposed location and granite topography ensure excellent visibility. On the occasional day that visibility at North Point is poor, it is usually caused by a local plankton bloom, which in turn attracts large filter-feeding fish. Whale sharks and manta rays are sometimes seen here; humphead wrasse can be spotted on most occasions. Schools of barracuda swim around a little way from the rocks; fusiliers and surgeonfish are other colorful sights. Moray eels are common, and even ribbon eels have been sighted from time to time.
The rocks and sand are covered with sea stars, sea urchins and sea cucumbers. Fast-moving invertebrates include crabs, lobsters, and shrimps. Octopuses are shy and difficult to spot, but cuttlefish swim around fearlessly. Turtles (green and hawksbill) can also be seen here. The banded sea kraits are extremely venomous but no danger to divers.
Located on the northwest ridge of island 9 (Ko Bangu), Christmas Point is a garden of large, submerged boulders covered with bright, colorful soft corals and sea fans. The site is suitable for intermediate to advanced divers; depth is from 10-50 meters, with most of the really amazing scenery at 20-30 meters. Visibility ranges from 20-30 meters, but on good days it seems to be infinite. The site is best as a morning dive.
The dive site is completely submerged except for the top of a huge boulder breaking the surface, which then drops down to over 20 meters. Huge boulders are scattered elsewhere, which create a variety of fantastic swim-throughs. The bottom is sandy, with very little coral growth; hard corals, in particular, tend not to grow here. There are some huge gorgonian sea fans which are well worth checking out for indications of macro life.
Fish species found here include great barracuda, giant trevallies, reef sharks and leopard sharks. Divers may also spot huge manta rays and, on occasion, the elusive whale shark. Schools of bait fish and glass fish abound, which attract devouring predators such as mackerel and tuna. Spiny lobsters can be seen lurking inside rock crevices; ribbon eels may be encountered, too. Closer to the shallow part of the site it is not uncommon to see hawksbill turtles roaming around in search of food.
Breakfast Bend is located on the east of island 9 (Ko Bangu) and is one of the best reefs in the northern part of the Similan Islands group. A shallow flat area rich in small coral interspersed with sandy patches runs from 0-8 meters; from about 8 meters down to 30 meters there is a gentle sloping reef featuring an abundance of hard corals and their inhabitants. Breakfast Bend is suitable for all levels, especially beginners and snorkelers.
Currents are usually weak to mild; if they come from the east they split in the centre of the bend, which is a good place for dive masters to choose which current to go with. There is enough reef on both sides of this bend to enjoy a full one-hour dive. The site is best dived in the morning (hence its name) since this is when the sun penetrates the water's surface and illuminates the diverse marine life below. This said, the site can be dived at any time of day.
The largest fish divers are likely to come across are leopard sharks or bluespotted stingrays, both of which spend most of the day resting on the sand. Large potato groupers and humphead wrasse are also big and easy to spot. Down on the seabed divers often encounter spotted garden eels living in huge groups in holes in the sand. Divers should also keep an eye out for whitetip and blacktip reef sharks. Other interesting creatures include ghost pipefish and hawksbill turtles.
Donald Duck Bay is a small bay at the northern end of island 8 (Ko Similan) and the most recognizable location in the Similan Islands. It boasts a pristine beach and unique rock formations that are easy and fun to climb. Many regular Similan cruise ships stop off here, as do liveaboard boats; it is the perfect place to moor up for the afternoon or night and explore. Diving here is good, but not nearly as challenging as most of the other nearby sites. Donald Duck Bay is suitable for all levels: even snorkelers, children and the elderly can enjoy themselves here!
The topography of this dive site is relatively flat, but becomes gradually deeper as it runs away from the beach. Maximum depth is 20 meters; currents are either gentle or non existent. The water is generally clear compared to other Similan Island dive sites, and much clearer than those in other parts of Thailand.
Coral clusters are everywhere, each with its own small community of reef fish and invertebrates, but divers are unlikely to see any large fish here. Octopuses are among the most popular invertebrates, but they are extremely difficult to spot. Their cousins, cuttlefish, swim around boldly and can often be seen in abundance. Moray eels are numerous too, although during the day they hide in holes and stick their heads out sucking water past their gills. Nudibranchs, starfish, sea urchins and sea cucumbers are everywhere; at night, lobsters, crabs and shrimps venture out and explore the bay.
Like the nearby Donald Duck Bay, Turtle Rock is a relatively shallow and easy dive site located near the northeastern tip of island 8, Ko Similan. It is suitable for divers from beginner to advanced levels. The site consists of huge granite boulders scattered down from the surface to depths of more than 25 meters. On either side of the piles of rocks and boulders there are fields of staghorn coral and gorgonian sea fans, along with soft corals and anemones. Moving into deeper water things becomes a little sparser and less colorful, but there is still plenty of marine life. All along the dive site, especially on the north side, there are lots of canyons and a few swim-throughs, mostly at depths no greater than 10 meters. Currents are seldom strong, and night diving is possible.
Other than turtles, the most popular attractions are spotted garden eels and bluespotted stingrays. Whale sharks and manta rays can also sometimes be seen. Like most local diving sites, there is usually the chance of seeing leopard sharks on the sandy bottom. Keep an eye open for medium-size bony fish such as oriental sweetlips, titan triggerfish, groupers, parrotfish and trevally. Smaller, photogenic species which are not too hard to spot include lionfish, angelfish and boxfish. In nooks and crannies you can always see moray eels waiting to come out and hunt. Invertebrates such as sea stars, nudibranchs, sea cucumbers and sea urchins can be seen during the day. At night, large crabs and lobsters come out in search of food.
Beacon Reef (sometimes known as Beacon Beach) is located along the eastern coast of the southern half of island 8, Ko Similan. The site is accessible to all levels of divers, including snorkelers. It is long and quite easy to dive; depths range from 8-30 meters; currents are usually light.
The site is also sometimes called Atlantis Wreck, after the sunken diving liveaboard boat which ran aground in 2002. The vessel collided with the corals in the reef and sank. She then slid backwards and now faces the beach. With her shallowest part at a depth of 16 meters and her stern at 30 meters, she is an interesting and relatively intact attraction. Plenty of medium-size reef fish swim around the wreck, but there is still a long way to go before she becomes a thriving ecosystem.
Unlike many other local dive sites, Beacon Reef is more coral than granite rocks. The sandy and coral seabed starts just a few meters from the surface; it drops gently at first, then steeply down to more than 30 meters. Staghorn corals and gorgonian sea fans dominate the marine environment, along with several other types of hard corals, interspersed with soft corals and sand.
Green and hawksbill turtles frequent the reef, and sea snakes such as the banded sea krait are common, too. Invertebrates range from tiny nudibranchs, shrimps and crabs to large cuttlefish and possibly an octopus or two for the sharp-eyed. The list of fish at Beacon Reef is almost endless, as it is such a large area with a healthy and diverse range of life. Around the reef and the wreck, divers will encounter various species of moray eels, batfish, trumpetfish and lionfish. Clown triggerfish and the more common titan triggerfish are usually easy to spot, too.
The site is named after an unusually shaped rock that juts out of the water southwest of Ko Similan (island 8). At low tide the rock resembles an archway. One of the more challenging Similan Island dive sites, divers should be experienced due to depth (most diving is at 15-30 meters) and the possibility of strong surge and currents.
The submarine topography at Elephant Head Rock consists of dozens of enormous granite boulders stacked on top of each other, forming a towering pinnacle which spans a height of 40 meters from the sandy seabed to the surface. With an abundance of reef life, great visibility, challenging swim-throughs, caverns and canyons, Elephant Head Rock offers excellent diving opportunities.
In addition to the corals and sea fans that flourish in the nutrient-rich currents, a profusion of marine fish and invertebrates make Elephant Head Rock their home. Common sights include turtles, great barracuda, sweetlips, giant trevally, blue ring angelfish, fusiliers, red fire gobies and rock wrasse. Several species of snapper frequent the site, and divers are often surprised by the schools of huge jacks passing by.
Deep Six is a collection of submerged boulders that tumble down from the northern tip of island 7, Ko Pabu. The topography is similar to North Point and Christmas Point, with a variety of interesting swim-throughs. Not for beginners and challenging even for intermediate divers, Deep Six is one of the more exciting dive sites in the Similan Islands. The site is deep (it drops down to more than 40 meters); visibility is excellent and the marine life abundant and diverse.
A mooring line to the west brings divers down to the center of the dive site, where scattered boulders provide opportunities for great swim-throughs. A large arch at around 22-24 meters on the western side will bring you into a maze of smaller swim-throughs lined with whip corals and sea fans. To the north (where currents tend to be stronger) are piles of boulders which extend down to maximum depths of 35-40 meters. Whitetip reef sharks can occasionally be seen in these deeper areas, as can larger rays and Kuhl's stingrays. There is a channel on the eastern side of the dive site which provides good shelter when currents are strong. Leopard sharks seem to enjoy these sheltered sandy areas. Towards the south of the dive site the boulders spread out into larger, sandy areas which run alongside the island at a depth of about 10 meters. Look here for red and purple fire gobies and nudibranchs.
Medium-sized reef and schooling pelagic bony fish are everywhere. Divers can expect to encounter rainbow runners, sweetlips, fusiliers, barracuda and trevally. Examples of smaller fish and invertebrates sheltering from danger include frogfish, pipefish, snapper, boxfish, red fire gobies, lobsters and shrimps.
West of Eden is located on the west coast of island 7, Ko Pabu. Sometimes classified as a drift dive, the site features large boulders and canyons to explore, and boasts an abundance of morays eels, reef sharks and turtles. This site is suitable for divers from beginner to advanced levels, though beginners need to be forewarned about the occasionally strong currents.
The dive site consists of two distinct areas. The southern area stretching from the mooring to the southern tip of the island is a hard coral garden at a depth 8-12 meters. This garden abounds with batfish, groups of brown parrotfish, Moorish idols, bannerfish and trumpetfish.
North and west from the mooring are some massive boulders and, at a depth of 20-30 meters, beautiful soft corals and sea fans. Between the boulders are a number of channels and crevices where divers have a chance of spotting mantis shrimp and nudibranchs. Reef sharks are plentiful, as are turtles. It is also quite common to see large schools of pelagic fish such as barracuda, giant trevallies and dogtooth tuna.
Running along the southeastern corner of island 7 (Ko Pabu), East of Eden is one of the most colorful and vibrant fringing reefs in Thailand. Featured in National Geographic, Scuba Diver magazine and numerous other publications, no visit to the Similan Islands would be complete without a dive along perhaps the most famous of all the islands' dive sites. West of Eden enjoys healthy, hard coral reef coverage in the shallows, which are teeming with colorful fish. There is also amazing granite boulder topography around which to dive and admire the profusion of gorgonian sea fans, acropora table corals and soft corals. The site is suitable for all levels.
The dive usually starts a short distance from the island's northernmost point, dropping down into a small sheltered bay. Visibility is generally good so you can wander along the reef looking for the batfish and turtles frequently spotted here. Some of the best parts of the dive are in the shallow areas where several large schools of yellow goatfish swim above the corals, while trevallies shoot across the reef hunting glassfish. Common reef octopus can also regularly be seen on the top of the coral, changing color as you approach.
At the southern end of the reef is an enormous coral pinnacle starting at a depth of 24 meters and rising to 10 meters. It is definitely worth swimming around slowly at least once. This pinnacle is home to many different large and small sea fans, enormous table corals, endless different-colored feather star worms and beautiful soft corals and anemones. Numerous types of fish are attracted to this pinnacle, but also look for the smaller species such as nudibranchs, cowries and, at the right time of year, the elusive ornate ghost pipefish. This pinnacle is truly a self-contained ecosystem.
Anita's Reef runs from the southern tip of island 5 to the western side of island 6. It is a perfect introduction to diving at the Similan Islands – a photographer's paradise and one of the most popular local dive sites. Conditions are ideal for divers of all levels. Depths range from 5-30 meters; visibility is usually about 20 meters; currents are generally mild.
The reef starts shallow at around 5 meters and drops to a depth of about 30 meters: it consists of a mixture of hard and soft coral pinnacles, white sand areas, and in the southern, deeper section, massive granite boulders. When currents are present they are usually mild, ideal for taking a closer look at some of the coral pinnacles which start at around 5 meters and are dotted over the white sand to a depth of around 24 meters. They consist mostly of large pore, table and compact corals and a mixture of beautiful red and pink soft corals and huge sea fans.
The highlight of the site is a spectacular rock pinnacle that rises from the sandy bottom to a depth of 12 meters. The rock is covered with hard and soft corals, and is teeming with invertebrates and bony fish, with occasional visits from marine reptiles The rock is also a superb night dive. At the southern end of the site are huge granite boulders adorned with green tree corals and falling to depths of 30 meters or more. Leopard sharks and stingrays can sometimes be seen lying here in the sand gullies.
Hide Away Bay (also known as Barracuda Point) is located off the south of island 5 (Koh Ha), not far from Anita's reef. It is an interesting dive site that combines the two most familiar Similan topographies: large granite boulders and coral reef. Weak currents and benign conditions make the site ideal for divers of all levels. Snorkelers can also participate in the fun!
The southern section of the dive is the deepest and where the large boulders are to be found. The deeper boulders have sheer, clean surfaces with little coral growth, but as you move into shallower waters the rocks have soft coral, gorgonian sea fans and sea whips attached, as well as sea stars, urchins and sea cucumbers. Bluespotted Kuhl's rays can be seen in the sand, as can black spot garden eels. Batfish are normally in evidence, along with emperor angelfish. Clown triggerfish can also be seen and sometimes a solo giant barracuda is spotted passing by. Blacktip reef sharks patrol the areas away from the reef.
To the west is the Tuna Wreck, a vessel sunk deliberately by the Thai authorities in 2003 to provide more diving opportunities at the Similan Islands. Most divers don't venture down to the wreck, however, as it sits on the bottom at 40 meters and even at its shallowest point is approximately 28 meters below the surface.
Shark Fin Reef, located about 1 kilometer southeast of island 3, is a formation of large granite boulders covered with hard coral and superb gorgonians sea fans. Normally 3 pinnacles resembling shark fins can be seen from the surface – it is these rocks which give the site its name. Most of the dive site is hard coral, soft coral and sea fans, with a maximum depth of around 35-40 meters. The site is best for experienced divers.
Dives usually start on the southern side of the ridge, which is a steep slope dropping into the sand at a depth of about 25 meters. Alongside the slope are a number of large boulders which provide hiding places for moray eels, lionfish and scorpionfish. The sandy patches between the boulders are a good place to find Kuhl's stingrays and leopard sharks. Humphead wrasse and humphead parrotfish can also be seen here, as can banded sea krait and perhaps a passing hawksbill turtle.
To the southeast is a large swim-through that provides an opening to the other side of the dive site. The marine life is more diverse there with clown triggerfish, halfmoon triggerfish and schools of batfish, pallette surgeonfish, blueface angelfish and bannerfish. Passing sharks and larger rays can also be spotted.
Boulder city is a submerged site about 1 kilometer off the east coast of island 3 and approximately 400 meters southeast of Shark Fin Reef. It is often visited as part of a liveaboard trip's final dives. As the name suggests, this dive site has a fantastic topography of large boulders, cliffs and rocks on a sandy bottom. The dive site is very open and unprotected; currents are often moderate to strong. It is recommended to keep on the calm side of the boulders during the dive. Ascent and descent is preferably done along the anchor chain. Depths range from 12-30 meters and visibility is usually excellent. The site is suitable for intermediate to advanced divers.
Divers enter the site at either the north end (right next to the southeastern tip of Shark Fin Reef) where the mooring is attached to the reef at a depth of 20 meters, or at the deeper south end. The decision will depend on the currents, which can be strong at times. Some divers will use the line to get all the way down to the bottom and then use the rocks and boulders for shelter while exploring the profusion of marine life. There is not a great deal of coral at Boulder City, but this doesn't reduce the quantity or quality of fish and invertebrates. The massive granite boulders are spread out in an unnaturally ordered way, making the dive site look like a huge loaf of sliced bread, with large rocks on the sandy seabed being the crumbs. Manta rays and whale sharks pass by from time to time, especially late in the diving season, but are by no means guaranteed. Reef sharks and smaller rays can usually be found on the sand surrounding the rocky dive site. Other species divers often encounter include Kuhl's stingrays, jenkins stingrays, leopard sharks, schooling barracuda, yellowtail barracuda, humphead parrotfish and oceanic trigger fish.