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Your Guide to Diving in Similan Islands

Thailand's Best Marine National Park

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...Highlights: turtles, schooling fish/big pelagics...
...Diving environment: beginner and advanced divers, very popular...

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 the dive sites feature 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.

In many ways Christmas Point is a dive site which 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. 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.
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How to Dive the Similans

To review your dive options, take a look at our Similan liveaboards or Khao Lak day trips 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.

The Similan Islands 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. For further reading on the climate in the Similans, visit The TravelerOpens in a new window.

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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Where are the Similans and How Do I Get There?

Review our maps below of the islands 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)

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

Useful References

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