Diving in the Similan Islands

Thailand's Best Marine National Park

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...Good for: Small animals, underwater photography, snorkelling, visibility, dive value-for-money and advanced divers...
...Not so good for: Non-diving activities...

Without question, the Similan Islands represent the best diving that Thailand has to offer. No other region offers such a number of excellent sites and such wonderful scuba diving as can be found in this protected national park. The Similans are a chain of 9 tiny and verdant islands fringed with white sand beaches and surrounded by some of the area's richest waters.

Liveaboard boats cruise around this picturesque scene stopping at the choicest sites to allow divers to explore at their leisure all the marine life that abounds: leopard sharks, white tip and black tip reef sharks, batfish, moray eels, snappers, barracudas, triggerfish, surgeonfish and unicornfish.

Snorkelling at Donald Duck Bay in the Similan Islands - photo courtesy of Marcel Widmer - Seasidepix.com
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On the eastern side of the Similan Islands, hard corals in big numbers cover the steep slopes down to the sea floor, with impressive table corals and staghorn corals being the most prevalent. Bommies bedecked with soft corals are a magnet for the sea life and dot the seabed.

Elsewhere, huge granite boulders, a dominant feature of diving in the Similans, rest mightily on the sandy sea bed and provide an imposing backdrop to all the fish action as well as being the canvas upon which is painted a riot of colourful soft corals and gorgonian fans.

Elephant Head Rock is named after the rock that sits out of the water and, to the imaginative mind, resembles a Pachydermal cranium. It is one of the dive sites where the stunning topography is the chief feature - with more penetrable holes than a Swiss cheese factory. Around this inspiring underwater scene you can check out all the resident sea-life including groupers, turtles, trevallies and reef sharks. Sometimes a little bit tricky with current but always exciting, Elephant Head Rock is a 'must do' site.

With impressive rocky drop-offs and huge gorgonian sea fans, West of Six has become a bit of a favourite thanks to several resident frogfish and ribbon eels, unusual sights in these waters. The shallow areas feature several canyons covered in hard corals and provide regular encounters with turtles, barracuda, batfish and octopus. A colourful dive site with fantastic landscapes, West of Six has something for everyone.

Christmas Point is a dive site which in many ways typifies the Similan Islands since it is dominated by the enormous granite boulders, arches and swim-throughs that make scuba diving here unlike anywhere else. Using the walls as substrate, soft corals and huge sea fans proliferate and act as the backdrop to the passing sharks, jacks and fusiliers. A dive site with impressive and unique topography, there are plenty of reasons to look forward to Christmas Point.

Given the diversity and convenience of such wonderful dive sites, it is little wonder that the Similan Islands continue to be a popular choice for discerning divers, many of whom return year after year.

Dive Site Descriptions

Anita's Reef - On the east coast of Similan Island No.5 you can find Anita's Reef. This is a gentle sandy slope boasting some stunning coral bommies and areas of both table corals and staghorn corals. Some of the fish life you can expect to see here are lionfish, the colourful Oriental sweetlips and the gorgeous but less commonly seen clown triggerfish. Show more

The coral bommies are covered in soft tree corals and sea fans that hide longnose hawkfish. The dendronephthya coral, in shades of golden brown and purple are the ideal hideouts of glassfish and juvenile fish. If you keep watching you'll see bluefin trevally darting in and out swiftly as they hunt the smaller fish.

Moving southwards there are often groups of spotted garden eels on the sandy bottom and blue-spotted Kuhl's stingrays buried in the sand. Here you can also see a type of filefish called a blue blanquillo as well as plenty of sea cucumbers. Look closely and you may be lucky enough to spot a whitepatch razorfish.

The Similan Islands are well known for their shrimp-goby symbiotic partnerships; the goby fish sharing its underground home with a snapping shrimp. The shrimp having poor eyesight relies on the goby to look out for danger, and the goby makes the most of having its very own cleaner! Speaking of cleaners, don't miss the sight of the common cleaner wrasses, among the coral bommies, cleaning the ears of divers!

The different coral areas are formed from staghorn and bottlebrush corals, sheet corals, knobbly finger corals, and the bigger species of lobed and star coral. Hiding in the nooks and crevices are Diana's hogfish and slender grouper.

Schools of blue damsels and jewel fairy basslets surround you, along with an amazing number of slender fusiliers. Larger fish here are the roundhead parrotfish and titan triggerfish feeding on the hard coral which are closely followed by yellowfin goatfish scrabbling for the scraps. Out in the blue you may see a majestic fantail stingray cruising past, looking very impressive at a full 2 metres long. Watch out for the giant trevally as they hunt around the boulders and large table corals that typify the underwater landscape of the Similans.

Anita's Reef is an easy dive site with gentle currents, making it an ideal check-out dive on a Thai liveaboard cruise.

Beacon Point - This site is located at the extreme south of Island no. 8 and features large patches of hard coral reef as well as huge boulder formations that rest from just a few metres below surface and drop down to almost 40 metres. The boulders are covered with hard corals and gorgonian sea fans. Show more

This is a good multilevel dive with interesting features at every depth. This south easterly reef is actually an extension of the lengthy sloping drop-off running parallel to the eastern coast (Beacon Reef), and very comparable to the latter except that there are more fish and larger corals, especially in the deeper waters.

The dive site offers you a good chance of seeing manta and eagle rays in the deep southern waters, away from the headland, as well as the usual leopard sharks and small reef sharks.

Making your way east in the direction of Beacon Reef, the bottom drops to the deepest level and on the white sand you can see many blue spotted sting rays. Black tip reef sharks often swim around the boulders and look out in the blue for white tips cruising past too. Usually the water is very clear around the boulders.

There is abundant healthy hard coral along the shallow reef top and the steep drop off which is a wall covered in clumps of gorgonian sea fans and wire corals. The reef-flat features many small boulders of lesser star and brain corals, interspersed with clusters of staghorn corals, all covered in colourful reef-fish like chromis, wrasse, parrotfish and surgeonfish. Other species of fish life here include firefish, scorpionfish and the unusual looking bigeye. Look closely at the coral formations and you will find numerous nudibranchs. The largest boulders offer shelter to red tooth triggerfish.

Further north where the reef meets with the southern part of Beacon Reef, there thrives what is said to be the biggest gorgonian seafan in the Similans. This great coral is more than 2 metres wide.

Boulder City - Located 1 km off the east coast of Koh Payan, Island number 3, and about 400m south east of Sharkfin Reef, Boulder City forms a chain of submerged boulder formations. Due to its southern location in the Similan Islands group it is often the last dive site visited on a liveaboard trip before the journey back to Phuket. Show more

Boulder City gets its name from the large granite boulders that are stacked on top of even bigger granite boulders sat on the sandy bottom. They provide an amazing underwater landscape and a great dive.

Dives at Boulder City can be challenging as the site is exposed and currents can be strong but for this reason it attracts bigger fish such as whale sharks and manta rays. Other sights to look out for include Napoleon wrasse, turtles, and trevallies hunting swirling schools of glassfish.

Giant barracuda, dogtooth tuna and mackerel are also common as this dive site has many cleaning stations. These stations also provide a great opportunity to see the very timid slender unicornfish up close. Some of the smaller species that you can see are jawfish, which is an endemic species to the Similan Islands, and purple and red fire gobies.

The boulders drop down deeper than 35m so typically the dive starts deep and gets gradually shallower as you work your way in and around the rocks. The boulders are generally smooth with few corals although there are patches of soft coral and crinoid growth. Golden gorgonian fans and sea whips feed in the currents at the sides and in the cracks of the boulders. Sea urchins can be found wedged into the cracks, along with lionfish, scorpionfish and large moray eels.

There is an abundance of algae growth here which attracts plenty of grazers, including both nudibranchs and fish. There are masses of unicornfish, butterflyfish and angelfish happily feeding away. In the deeper sections, there are many red and white whip corals and here you are likely to spot small schools of Oriental sweetlips, blue-lined snapper, barracudas, grouper, triggerfishes, parrotfish and filefish. Leopard sharks and Kuhl's stingrays are frequently seen on the outlying sandy bottom of the deeper areas as well as white-tip reef sharks.

As this is one of the more advanced Similan dive sites, it's a good idea to end your dive in the middle of the site at the shallowest boulder outcrop. Here you can reduce your exposure to the strong currents that are sometimes running. However there are mooring lines on the site too that can help with your descent and ascent. Longfin batfish, black damsels and fusiliers are likely to accompany you on your safety stop.

Breakfast Bend - The unusual name of Breakfast Bend comes from the gorgeous dawn light that you can experience here in the early mornings. This dive site is located on the east side of Koh Bangu, Similan Island number 9. Show more

The reef life here is prolific and, although the southern part of this island suffered some damage from the 2004 tsunami, the coral in deeper water here is still in pretty good condition. The reef is mostly hard coral. Staghorn coral is a dominant species with cabbage coral, brain coral and particularly table coral found here as well. On the steep reef slope there are larger but a less dense amount of corals, particularly plate corals.

This is an easy going site, suitable for all levels of diver and is often used as a check-out dive at the beginning of your liveaboard trip. It's also a great site for snorkelers especially as there are plenty of sergeant major fish, busying about the corals. The reef starts at 5m from the surface and descends down to 18 metres then steep banks drop to 34 metres. Much of the dive will be spent between 10m and 20m where angelfish, bannerfish, triggerfish, grouper and parrotfish are just some of the many fish you'll find.

In the shallower water you may encounter a nocturnal leopard shark dozing on the sandy bottom as well as Kuhl's stingrays. Octopus can also be seen here and in the deeper water, black-spot garden eels.

At the south tip of the dive site the reef is replaced by large boulder formations that lie in deeper water. The rocks are arranged in such a way that they provide several swim-throughs and small channels where you might even encounter white-tip reef sharks. This area lacks corals but the stronger currents bring in cobia, large tuna fish and schools of chevron barracuda. These fish frequent the more exposed areas of the Similans in search of food so there's a good chance of a sighting.

Chinese Wall - Located at the southern point of Koh Miang, Island number 4, Chinese Wall is named after the collection of granite boulders that stretch away from the southern point of island. The boulders begin above the surface and continue down underwater to a depth of almost 30m. These rocks form the swim-throughs, valleys, caverns and caves that make this site a diver's playground. Show more

The crevices are home to large giant moray eels as well as the finbriated moray, yellow margined moray and smaller white eyed moray. The eels are often seen being groomed by cleaner shrimps. The shrimps feed off the eels' skin, picking off bits of algae, loose skin and parasites with their claws; another one of the many symbiotic relationships to be observed when scuba diving in the Similan Islands.

Moving along, more boulders form large overhangs and tunnels. Keep your eyes peeled and you may be lucky enough to see one or two of the resident white tip reef sharks hiding in the shadows. Some are up to 2 metres long. Bumphead unicornfish also take refuge in the cracks and crevices.

In the shallows you'll see parrotfish, fusiliers, surgeonfish and soldierfish. Look out for harlequin sweetlips and oriental sweetlips too. Trumpetfish and cornetfish are also numerous.

Also known as Bird Rock, Chinese Wall is a great site and often the envy of divers as many boats don't stop here. Currents are usually moderate although sometimes they can be strong. Visibility is often good, above 20m. It is a good idea to carry a torch on this dive to reveal the true colours around the rocks at depth and find fish lurking in their hideouts.

If you do get the opportunity to dive here you may also get to go ashore to visit the beach while your boat is moored up. There is a small national park ranger station here and a trail which leads to another beach and a small holiday home belonging to the Thai princess.

Coral Reef - Located on the north side of the tiny Koh Ha, Island number 5; Coral Reef is a pleasant dive site for all abilities and a maximum depth of 30m. Your dive will most likely start at the deepest point and get progressively shallower with much of the marine life between 8m to 15m deep. This is also a great site for snorkelers. Show more

At the deepest point you're likely to disturb one or two blue spotted Kuhl's stingrays buried in the sand. They are expertly camouflaged with only their eyes protruding until they sense intruders and suddenly swim away at surprising speed. As you start to make your way from the edge of the reef across the white whip coral beds, you may well see patrolling black tip reef sharks. Groups of garden eels sway gently in the current before diving into their holes to hide from divers.

As you progress steadily shallower, schooling bannerfish hang in congregations along with smaller numbers of moorish idols. The inquisitive longfin batfish also hang out in small schools. Out in the blue the occasional great barracuda can be spotted too. The common fish here include black and white snapper, yellowhead snapper, fusiliers, surgeonfish and sweetlips.

Giant moray eels make their home in small holes and tunnels on the reef. Although their teeth and length can make them look menacing, these eels are usually harmless. In the Similans they are mostly yellow, green or brown in colour and can reach 3 metres in length, Sea snakes can also be seen here and although they are very venomous they are completely docile and their jaws are not big enough to bite a human limb.

The reef is shallow enough to spend your safety stop searching for critters and marine life hiding in the cracks and crevices of the ledges - you never know what you might find!

Although not as exciting as some of the other Similan diving sites, Coral Reef offers a pleasant and interesting dive experience.

Deep Six - Located just to the north of Koh Pabu, Similan Island number 7, Deep Six is, as the name suggests, one of the deeper sites you're likely to encounter in the Similans. Huge granite boulders form a rocky V-shaped ridge that starts just 5m below the surface and plunges down beyond 40m. The 'V' points north into deep water and the sides of the 'V' form the reef slopes of the island. Show more

Currents can be strong at Deep Six so this is a dive site for intermediate to advanced divers. The best section of the site is located to the north and close to the rock jutting out of the water and marking the location. The best plan is to go deep out to the north to start with and make your way back up along the ridges.

Descending down the buoy line here, there are several spectacular swim-throughs, at about 10m or so. Corals include small table, wart finger and leather corals. It's easy to spot boxfish, lyretail grouper and the gorgeous powderblue surgeonfish. Butterflyfish, bannerfish and Java rabbitfish are also common schooling residents.

The boulder ridges house gorgonian sea fans, table corals and featherstars, with sea cucumbers and blue sea stars also hanging on. Moray eels are numerous and you can see emperor angelfish, parrotfish, and triggerfish.

Fusiliers are many in number and this of course attracts the larger hunting fish such as bluefin trevally and giant trevally. You may even see dogtooth tuna approaching causing the fusiliers to scramble for cover. If you're looking for pelagic action then you may be lucky enough to see a passing whale sharks or a manta ray. Barracuda are also commonly seen cruising out in the blue.

As you dive deeper then blue-spotted sting rays are in abundance, along with circling white tip reef sharks and leopard sharks resting on the bottom; all common sightings at the Similan Islands.

Deep Six was one of the Similan dive sites that suffered damage during the devastating tsunami on 26 December 2004. Consequently there is little healthy coral in the shallows but, as the name suggests, all the fun to be had here is found in the deeper areas.

Donald Duck Bay - Donald Duck Bay is located on the north side of Island Number 8, and is named after a rock on the north side of the bay that looks like Donald Duck's head. The rock is the most recognised and photographed landmark in the Similans and is best viewed looking in from the outside of the bay on the east side. Show more

Like other dive sites of the Similan Islands, the boulders that run out of the bay on the northern edge form several swim-throughs, and house many interesting crustaceans. The molluscs, gastropods, crustaceans, and cephalopods are particularly healthy and large here due to the amount of food and scraps that find their way into the bay. Among the rubble of rocks on the bottom you can see decorator crabs, huge bull crabs, squid and cuttlefish. Painted rock lobster and red octopus can also be seen.

Several coral bommies separated by patches of sand are homes to an array of different shrimp species which can be heard crackling away on the dive. Moray eels can be seen swimming at night too.

Green turtles are also commonly spotted here as the bay is home to several large, friendly ones. The turtles have developed a liking for bananas but please remember they are wild animals and this is not their natural food source. While at the Similans please don't throw anything overboard or try to feed any of the fish or marine creatures.

If time permits, you can climb the rock between dives and enjoy the gorgeous panoramic view of the surrounding islands and the turquoise waters below. The island has a national park camping area and Donald Duck Bay is one of the most popular mooring spots for both day trippers and Similan liveaboards. The bay provides good natural shelter and many of the boats spend the evening here. It's not the best dive site but the bay is great for night diving.

Elephant Head Rock - Located between islands 6 and 7, Elephant Head Rock, or Hin Pusa, gets its name from a rock that sticks out of the water and resembles a half submerged elephant. This site is another Similan favourite and its huge granite boulders have created a myriad of amazing swim-throughs, tunnels and caverns. Show more

The site plunges to a maximum depth of 50m but 30m is deep enough for most divers. You will probably begin the dive around the deep rocks where you might spot whitetip reef sharks and leopard sharks. Look in the sand for the purple fire gobies that like the deep water, and the rare McCosker's dwarf wrasse. A little shallower is the endemic Similan Islands jawfish.

As you follow the steep channel down through the big boulders watch out on the largest boulder for a small deep yellow sea fan. If you look closely at its fronds you'll find a family of spider crabs and near-by are large black egg cowries. You may see cuttlefish and mantis shrimps as you descend lower. The odd olive Ridley's turtle or hawksbill turtle can sometimes be seen in among the hard coral.

Weaving through the swim-throughs and channels look under ledges as you may see nurse sharks. These archways are lined with soft corals and seafans and are full of marine life. You'll see busying blue-ringed angelfish, bicolour parrotfish, titan triggerfish and the Andaman sweetlips, which is only found in this part of the world. Yellow goatfish and snappers are often found at the deepest levels, as well as several species of lionfish and grouper.

On this dive, it's a good idea to have a torch to search in the darker areas and to bring the soft coral colours to life. Search under the overhangs to find several species of the larger snappers, such as mangrove, one-spot and black and white, as well as giant sweetlips.

Giant trevally can be seen darting past in their mating dance. You may also see powder blue surgeonfish feeding on the algae along with bigeye bream and large schools of robust fusiliers.

At the most southerly tip of Elephant Head there is a small group of pinnacles submerged in the deep water. This is an exposed area meaning it may attract some large visitors such as manta rays and even whale sharks. Due to the possibility of strong surge and current, this is one of the more challenging dive sites in the Similans.

Hideaway - Located just off the southern point of Koh Ha, Island no. 5, Hideaway is often referred to as 'Barracuda Point', however schools of barracuda are not that common here any more. Show more

This is an interesting diving site which combines some of the best features of the different topographies that dominate the local seascape. Some parts of the dive are mostly large boulders and other sections constitute fringing coral reef. The visibility is generally good here, above 20m and currents are normally mild so this site is suitable for all levels of diver. The maximum depth is 35m and the reef rises up as shallow as 7m.

The southernmost area of the dive is the deepest and here you'll find the largest sunken boulders that typify scuba diving in the Similans. These deeper, more isolated boulders resting on the sandy sea bed have smooth, clean surfaces with little coral growth, save for a few clinging dark green branching cup corals. Look on the sand to see the occasional blue-spotted Kuhl's stingray as it hurriedly darts away from you. Black-spot garden eels can also be seen here. By the southwest corner of island 5 is the wreck of a Taiwanese fishing boat, 'The Tuna Wreck', sunk by the national park in 2003 and sitting between 26 and 40 metres.

Most of the splashes of colour are provided by the clown triggerfish as it explores the rocks. Batfish are normally in evidence along with emperor angelfish. You may spot a solitary great barracuda out in the blue away from the reef as well as schools of yellowfin goatfish that add yet more colour.

Moving shallower and further north, the rocks are alive with soft corals and sea whips. You'll notice plenty of sea stars, urchins and sea cucumbers as you come to the sloping reef at around 20m. The reef is home to schooling bannerfish, moorish idols, trumpetfish and dogfaced pufferfish. Oriental sweetlips are often seen resting under the table corals. Checkered snapper and blue lined snapper are common, as are bicolour parrotfish, wrasse and fusiliers.

Further on you come to a series of small structures set up by the national park in 2005 as a memorial of the tsunami. They are set in about 10m depth, just as the flat sand starts to slope down. There also a couple of small statues of mermaids in this same area, which is often used for night dives.

To the far north is a section of shallower reef covered in mosaic and star brain corals along with lobed pore corals. You can see small groups of common lionfish here, hiding out under the seclusion of the domed coral colonies. Powderblue surgeonfish and orangespine unicornfish feed on the coral surfaces while red fire gobies flit about above the sand. Reticulated damselfish cover the fingers of the knobbly wart corals as black pyramid butterflyfish glide gracefully through the shallows.

North Point - Located about 50m out from the north side of Koh Bangu, Similan Island number 9, North Point is the most northerly tip of the island chain. As it is just east of Christmas Point, it offers similar conditions - a huge granite boulder dive site where currents can be strong. Visibility is generally excellent between 20-40m. Show more

Normally there is a mooring buoy available for descents. The boulders reach a maximum depth of 35m and rise to 8m, forming some fantastic swim-throughs and channels along the way. Soft corals and crinoids cling to the smooth rock surfaces along with seastars and pincushion starfish. At the base of these stones you can find ribbon eels and mantis shrimps. There is also an abundance of jacks, surgeonfish and fusiliers here too.

This is another fantastic Similans dive site for underwater photography and perhaps a passing pelagic sighting. This site also gets its fair share of manta rays that come to use the cleaning stations. Don't forget to look out in the blue and above your head for a passing large shoal of chevron barracuda too, that frequently patrol North Point.

In the shallows closer to Island 9, between 8 and 14m, there are enormous flat plains of cauliflower leaf corals and stubbly finger corals. Green and hawksbill turtles are common here. As usual, leopard sharks can be seen in the sand at the bottom of the boulders. Other interesting marine life include large groupers.

Further north there is a white sandy floor at a depth of 40m that connects North Point to North Point Pinnacle. When conditions are right you can dive from the pinnacle that begins at 24m deep and drops down to over 50m. Below you, it's possible to see sharks resting peacefully and sometimes you can encounter a manta ray here.

This is a stunningly beautiful dive site, especially when the visibility is good and there is no current.

Sharkfin Reef - Running from Island No. 3 and extending all the way to Boulder City, Sharkfin Reef is a long submerged rocky ridge. At low tide the ridge breaks the surface of the water to resemble a shark fin. Show more

The site provides dramatic and contrasting scenery to those dive sites found on the eastern sides of the Similan Islands. The reef is made up of a series of massive granite boulders covered in gorgonian seafans and a variety of hard corals. It is like 2 different sites in one and can be dived more than once.

On the north-eastern side is a sloping reef of stacked boulders covered in hard corals and on the south west the boulders create a more prominent drop-off into deeper water resembling an underwater canyon. A large swim-through makes a natural passage way from one side to the other but be careful as you go so that you don't damage the delicate hard coral growth.

The reef has some prolific and diverse marine life with large cube boxfish, clown triggerfish, half-moon triggerfish, schools of batfish, palette surgeonfish, blue-faced angelfish and bannerfish. Look out for smaller marine life in among the rubble on the sand between the coral patches. Leaf fish are seen here as are blue ribbon eels. Nudibranchs are numerous too.

The deeper side is a good place to spot passing sharks and larger rays. Also look out for Napoleon wrasse, bumphead parrotfish and leopard sharks.

This is an impressive site and is often visited as one of the last dives of a liveaboard safari.

Three Trees - Located on the north east corner of Koh Bangu, Similan Island number 9, Three Trees, formerly known as Batfish Bend, gets its name from the row of 3 trees on the edge of the island. While the 3 trees may be dead, the marine life proliferates here. Show more

This site boasts amazing diversity but is infrequently visited by the Similan liveaboard cruises and has therefore become one of the more enviable of its scuba experiences. It's a beautiful site to dive in the morning when the eastern sunshine penetrates the reef.

The reef starts at around 8m below the surface and descends down to about 30m. The healtier corals are found at deeper section of the reef. Common fish at the dive site include raccoon butterflyfish, Meyer's butterflyfish, humphead unicornfish, oriental sweetlips, harlequin sweetlips, soldierfish, powder blue surgeonfish, squirrelfish and bigeye. You may spot a red-toothed triggerfish either swimming high above the reef or resting among the corals. This particular species is named after the colour of its front teeth and not the colour of its amazing blue body.

Look out also for blackbelt hogfish hiding out under the table corals. Adults have red heads and yellow tails while the more timid juveniles are dark brown with bright yellow spots. The larger fish that may be seen here are brown marbled grouper and large blue yellowtail emperors.

Napoleon wrasse are sometimes spotted here too. These gorgeous fish have been so extensively hunted in Thailand and other parts of Asia for fish markets that their numbers are now dangerously low.

Turtles, always popular with scuba divers, will often make an appearance ripping up the coral as they feed. They share their food with parrotfish which are often followed by goatfish hoovering up the remains. Titan triggerfish are also found here munching on staghorn coral and sea urchins.

At the deepest part of the dive, several large boulders lie decorated by gorgonian and knotted sea fans. The fans host feather stars and cleaner and multibar pipefish - strange red and white striped creatures. Many nudibranchs make this area their home along with huge sea cucumbers - some as long as half a metre.

Leopard sharks can be spotted resting on the sandy bottom just at the edge of the reef or around the boulders in deeper water. The boulders also act as cleaning stations for larger fish such as dogtooth tuna and chevron barracuda.

All-in-all, this site has plenty to please even the most discerning diver.

West of Six - Also known as West of Eden, this site has increased in popularity over recent years since it boasts some of the Similans' best shallow coral coverage. This feature, combined with its more typical granite boulder topography, make West of Six a popular dive site for liveaboards. Show more

You will probably begin this dive by dropping in a sheltered bay in an area where turtles and batfish are a common sight. You can enjoy the shallows at this site where healthy acropora table corals and gorgonian sea fans provide a backdrop to trevallies hunting glassfish, large numbers of yellow goatfish, and the occasional inquisitive octopus.

For less experienced scuba divers, the shallows on the top of the boulders are a great place to spend the whole dive. If you want to venture deeper down through the rocky channels, you might be rewarded with sightings of frogfish, ribbon eels, giant morays being cleaned by white-banded cleaner shrimp, and possibly even a resident blotched fantail ray of impressive proportions.

You may wish to spend more time in the deeper section than your bottom time allows, so diving on nitrox is advisable to get the best out of West of Six. As you run down the contents of your tank in the shallower water, you can amuse yourself by seeking out the mysterious ornate ghost pipefish or tiger cowries. Alternatively, the blue is also a happy hunting ground for dive sightings, with turtles and great barracuda being known to put in appearances on the safety stop.

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Diving Season

Early November to early May is the period during which liveaboards operate at the Similan Islands. Day trips and overnight trips run from October through to May. The most constant weather patterns, and therefore the most stable conditions, tend to be between February and April. The diving at this time of year is great as the visibility is always between 25-40m, and calm seas are the norm as the monsoon winds cease to blow. Clouds are rarely seen in the sky.

The Similans are only 8 degrees north of the Equator and therefore exhibit a tropical climate, including a water temperature that usually ranges between 26-29°C, being warmest towards the end of the season (February-May). Even at depth, the water is usually only 1 degree less than at the surface. Similarly, the light conditions are good as divers descend to depth.

Currents tend to be stronger towards the end of February, making drift dives more interesting and also attracting more pelagics in the area, such as manta rays and whale sharks. Green and hawksbill turtles are often seen at the dive sites. Their breeding season is from November to February.

Being closed for 6 months of the year, the dive sites have a much needed period of recuperation from the effects of constant diving and boats operating in the area during the main season. This closed rainy season fortunately co-incides with a period of spawning for many of the fishes.

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How to Dive the Similans

To review your liveaboard and daytrip options, take a look at our website sections:

When choosing your Similan scuba diving trip there is really no substitute for a liveaboard. There is no other way to visit all 25 or so scattered sites at your leisure. Furthermore there is such a range of liveaboards in the area that there is something for just about every taste and budget, whether you are seeking a rough-and-ready backpacker trip or a deluxe 5 star cruise. Trips range from a standard 4 night cruise to 9 or 10 night safaris that visit Burma too.

You can however, get a taste of the Similans by doing one of more day trips from Khao Lak or Phuket. The journey times are greater (45 or 90 km away, respectively) for a smaller reward, but if you are short on time or don't fancy staying on a boat for a few nights, then this may be the choice for you. You can check out our day trip packages, which can be both with or without accommodation, in our Khao Lak day trip and Phuket day trip sections.

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Where are the Similan Islands and How Do I Get There?

Review our maps below of the Similans and their host country Thailand. Here, you will find information on how to get to Phuket or Khao Lak, and then on to the Similan Islands.

Map of the Similan and Surin Islands (click to enlarge in a new window) Map of Thailand (click to enlarge in a new window)

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Reef Summary

Depth: 5 - >40m
Visibility: 20 - 40m
Currents: Moderate
Surface conditions: Calm
Water temperature: 26 - 29°C
Experience level: Intermediate - advanced
Number of dive sites: >25
Distance: ~90 km north west of Phuket (5 hours), 65 km west of Khao Lak (3 hours, or 1½ hours by speed boat)
Recommended length of stay: 4 - 6 days

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Useful References

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