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Khao Lak Liveaboards
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Similan diving, including Koh Bon, Koh Tachai and Richelieu Rock is the best Thailand scuba diving on offer. The topography of the dive sites is varied, the water is crystal clear and sometimes the Similan Islands can be full of surprises.

Diving in the Similan Islands
Join our unique Khao Lak diving day trips on a traditional Thai longtail boat and dive the fascinating Boonsung Wreck

The Similan Islands National Park is open now until end of April 2015!

Until then, no liveaboard operations and no daytrips will take place. If you have any questions concerning a visit to the Similan Islands ask our experts.

read here: further information:


The diving season is from mid October to end of April!

From May to mid October the Similan National Marine Park is closed and entering within these months is illegal and also highly dangerous because of the prevailing weather conditions!


Coral grouper amongst healthy coralsThe 2014 - 2015 Similan diving season began in earnest on 15th October. Most scuba diving operators took full advantage of the early opening of the Similan National Park and favourable weather conditions in the last half of October. The first reports of diving conditions are very positive. After Thailand’s hot season, followed by a fairly mild rainy season, there is little evidence of any significant negative effects on the corals and marine life.

The start of any particular diving season often bears scars of heavy fishing activity during the low season months when the Similan Islands are closed to supposedly give marine life a chance to recover. This does not seem to be the case this season. Though fish stocks are not quite as healthy as in May 2014, suggesting some illegal fishing has taken place, fish stocks in general at this point in the season seem more abundant than in previous years.

Larger pelagic fish can be seen at many Similan dive sites, including dog-tooth tuna, travelly, barracuda, snapper and rainbow runners. Although depleted there are still sizeable schools of Chevron Barracuda at both Koh Tachai and Richelieu Rock.


The 2013 - 2014 diving season saw a vast improvement in the coral life at the Similan Islands. Coral bleaching in 2010 affected many dive sites across S.E. Asia with the Similan dive sites being some of the worst hit in the entire region. New coral growth was observed in 2011 - 2012, yet this did little to improve the overall look and feel of the dive sites.

Strong prevailing northerly winds caused water temperatures to cool in the Andaman Sea at the end of 2013 and this had a dramatic effect on the Similans as a whole. Not only were the cooler water temperatures attributed to a rise in marine megafauna sightings but also more rapid coral recovery. New coral colonies began to sprout on many Similan dive sites and existing new coral grow flourished.

Better all round Similan diving in 2014 so farBetter all round Similan diving in 2014 so far

The shallow waters around the islands had been the worst hit by coral bleaching, therefore it was very positive to see a lot of the new coral colonies forming up to a depth of 5 metres below the surface. Some of the best dive sites to benefit from new coral growth are Christmas Point and West of Eden in the Similan Islands and the northern part of the reef at Koh Bon.


A lot of focus has been put on whether 2014 - 2015 could live up to the latter half of the 2013 - 2014 Similan diving season, when whale shark and manta ray sightings rose dramatically. Since 2011 only a handful of whale sharks had been spotted each year. Early signs are very positive indeed. Several whale sharks have already been sighted at Richelieu Rock, Koh Tachai, Koh Bon and at Elephant Head Rock in the Similan Islands. (Read more about the sensational Similan Islands at the end of 2014 season here.)

Manta Rays typically migrate through the region from January to March yet several have already been sighted at Koh Bon and Koh Tachai. Although it is not uncommon to see Manta Rays this early in a season, sightings are usually brief with one individual being observed from a distance. Up to four Manta Rays have been spotted on a single dive at Koh Tachai with some of the individuals interacting with divers.

More Whale Sharks seen Similan DivingThe end of 2014 saw a dramatic rise in Whale Shark sightings

It might take several more years for the Similan Islands to see broader or even complete recovery, but there is definitely a more optimistic feeling so far, at the start of the 2014 - 2015 season.

With diving activities well underway conditions should only improve over the next six months. With each passing full moon there should be a marked increase in fish stocks. Plus with fingers and fins crossed, the whale shark sightings will hopefully continue.

Adverse weather mainly due to climate change may hamper some trips in November and December, as has become more common over the past few years, so be sure to check our weather updates and information before heading out to the Similan Islands during this period.

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Turtle at Breakfast Bend in the Similan IslandsIf you are a novice diver, diving Similan Islands is often a wonderful experience. Many of the sites offer easy diving conditions, crystal clear water and the good chance to see firm favourites such as turtles, anemone fish, moray eels, stingrays, pufferfish, lion fish, batfish and occasionally larger pelagic species such as barracuda and trevally. If you include diving at Koh Bon which is often included in a weekly Similans schedule then there is a good chance to see Giant manta rays at certain times of the season. The diversity of dive site types is a strong point of the Similan Islands. Gentle sloping coral reefs form on the east side of the islands, while rocky reefs dominate the west sides. There are also a number of submerged pinnacles that form dramatic underwater seascapes and create adventurous dives through caves and swim throughs which adds appeal for more experienced divers.

If you are a more experienced diver or have already logged a lot of dives at some of the world's great locations (e.g. the Red Sea) you may find similan diving not quite what you expected. Apart from notable Similan dive sites such as Elephant Head Rock, Christmas Point and West of Eden you will find the dive sites to the north of the Similan Islands more fitting to your experience level and expectations. Koh Bon, Koh Tachai and Richelieu Rock are more advanced dive sites and due to positioning and stronger currents offer a better chance to see larger marine life. Manta ray sightings that were previously declining, are now much more frequent at Koh Bon and Koh Tachai, especially between the months of January and March. Whale shark sightings are also becoming more common at Koh Tachai and Richelieu Rock with the occasional sighting at Koh Bon and even in the Similan Islands. Abundant soft corals and sea fans, coupled with large quantities of fish life and larger pelagic species, set Koh Tachai and Richelieu Rock in a much higher class of diving.

Do not expect to be alone at the Similan Islands. With all guide books, internet sites and local operators selling the Similan Islands as one of Thailand's top destinations you will find the islands and dive sites crowded. Unless your Similan Island trip includes divers, snorkelers or beach lovers in one group, avoid trips to the Similan Islands offering all activities from only the one large vessel, otherwise you will be snorkelling at dive spots or diving snorkelling spots whilst feeling the tremendous time pressure to complete your planned day! Thailand Dive and Sail recommend trips that separate their diving and snorkelling activities, with fast transfers to the Islands and also offering weekly schedules that include the better diving at Koh Bon, Koh Tachai and Richelieu Rock. Boats offering only a Similan Island and Koh Bon weekly schedule are not offering you the best of the Andaman Sea area.

Our photo blog, updated daily, gives a perfect overview of what you can expect to see diving the Similan Islands, Koh Bon, Koh Tachai and Richelieu Rock. You can browse the photos by serval categories including by dive sites, by locations and by fish common names and species names.

Interested in diving with a highly experienced and knowledgable team in the Similan Islands?

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If you plan your similan diving activities to be conducted as day trips, Thailand Dive and Sail recommend the following trips for the scuba diver who wants to get the most out of their limited time in Khao Lak.

A day trip to Richelieu Rock must top the list. This is by far Thailand's premiere dive site. We offer a fantastic speedboat day trip to Richelieu Rock. Diving from our speedboat limits the number of divers jumping in at the same time whilst every attempt is made to jump in at different times from the busy live aboard schedule operated at Richelieu. Fast transfers to and from Richelieu Rock means a later pick-up time in the morning and an earlier arrival back at you hotel.

A day trip to either Koh Bon or Koh Tachai to hopefully dive with larger marine species such as Manta Rays. Thailand Dive and Sail offer a speedboat trip which visits both of these top destinations in one dive day.

Check our new revisied Similan day trip diving information.

A local dive trip to the amazing Boonsung Wreck, just off Khao Lak's coastline. Thailand Dive and Sail offer a true Thai diving experience to the wreck. Our traditional longtail boat departs directly from one of the areas most beautiful white sandy beaches and takes a mere 30 minutes to reach the dive site. Although the visibility is often not as clear as the islands further out in the Andaman Sea, the quantity and quality of the fish life there is surpassed only by Richelieu Rock. Experience has shown us that the wreck is regularly quoted as one of the best dives on offer.

During peak season 2014 - 2015 Thailand Dive and Sail will operate a more private, intimate speedboat trip to Richelieu Rock every Monday. From January 2015 when the Manta Ray season really kicks in we will also be offering Manta research trips to Koh Bon. These trips are purely focussed on Manta ray education, conservation and you will have the direct opportunity to contribute to Manta ray research through photographic ID. Please contact us if you would like more details of either of these trips.

If you have the time, by far the best way to maximise your dive time in the area is on a Similan Island Liveaboard. You get the chance to see the Similan Islands at quieter times of the day and spend some time on the beaches there before heading north to the better dive sites. Most live aboard trips are four day/four nights although Thailand Dive and Sail also offer flexible two, three, four and five day trips. Read more about Similan liveaboards. Similan Island Liveaboard

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Outstanding Dive Agency

"What I realized when booking a day trip for diving in Khao Lak is that most of the companies are agents that book you on other companies' boats but provide you with the equipment. I emailed with both Ric and Sam at Thailand Dive & Sail in advance of our trip and they did a great job of evaluating the various choices of boat companies and dive sites relative to our experience. Ultimately, we ended up diving at Richelieu Rock on the Blue Dolphin, which is operated by Big Blue. The equipment that Thailand Dive & Sail provided was first rate (and far newer and in better condition than any of the equipment that the other folks on the boat had). The boat and crew were also excellent. The diving groups were small. For us it was one divemaster and three divers. The coral formations and sea life at Richelieu Rock were unforgettable and the service and food on the boat were great. We highly recommend using Thailand Dive & Sail."

★★★★★ by trat10 10.04.2013


Follow these quick links for our new and updated liveaboard information

Monthly liveaboard schedules

Read our liveaboard dive logs on our blog


Thailand Dive and Sail LogoThe philosophy behind Thailand Dive and Sail is to provide divers with the right trip tailored to their needs. Built up of a small team of experts who have dived in the Similans for more than a combined 25 years, our knowledge about this amazing Thailand diving destination is almost unrivalled. Read more about Thailand Dive and Sail


Ric Parker
Ric Parker

“My story of getting into scuba diving, and then shark conservation, is a story that starts with me ‘not’ getting into scuba diving, mainly because of a fear of sharks.

Back in 2001 I had been in Thailand for 3 weeks and was snorkelled out. I was really nervous about the diving... Read more...

Ric Parker
Clive White

Clive has always had a close affinity with the sea; he grew up in the south of England from the age of 12 and the sea was never far away.

The ocean beckoned from a young age and he spent a lot of his childhood either sailing or windsurfing... Read more...


The Similan Islands

Similan Islands
Similan Islands facts
How to get to the Similan Islands
Similan scuba diving
Similan dive site guide
Similan snorkeling
Similan sailing
Similan Islands accommodation

Further Similan Information

The updated Similan Island diving guide
Current diving conditions of the Similans
Similan diving daytrip itinerary
All about Similan liveaboards
Liveaboard Guide - What To Take
Typical Similan liveaboard route


Aqua Lung Partner Centre Scuba Schools Imternational Shark Guardian Shark Guardian Get Sharks Off the Hook
Thailand Dive and Sail • 4/88 Soi Bang La On Moo 7 • Khao Lak • A. Takua Pa 82190 Phang-Nga • Thailand

   Tourist Authority ThailandTAT Number: L.34/00715

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