The Similan Islands National Park is currently closed until October 2019!

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.

The Similan Islands are one of the most beautiful destinations that you will find in Thailand.

We have outlined activities that are available, including diving and snorkelling, plus information about the sites you will see both underwater and above. There are details about liveaboards and about sailing in the Similans, with some accommodation options too. All you need to know about these stunning islands on the west coast of Thailand.

Overlooking a bay in the Similan Islands


Immerse yourself in clear blue waters, play on peaceful white sand beaches and spend your days discovering the abundant tropical wildlife ecosystems of the Similan Islands.

Overlooking a bay in the Similan Islands


The Similan Islands are located 65 kilometers off the coastline of Phang Nga province in southwestern Thailand and were established as a National Park marine reserve in 1982.

In 1998 the National Park was extended to encompass the two neighbouring islands Koh Bon and Koh Tachai. The world-famous Richelieu Rock of Mu Koh Surin National Park is only a short journey away too. The Similans are a must for all visitors seeking the adventure and beauty of isolated island landscapes and a stunning underwater world teeming with unique marine life.


The history of these islands stretches far back in time. Thai Malays in the South of Thailand and in the Northern Malay state of Kelantan, speaking the Yawi language, travelled in this area and would refer to the Islands as the “Nine Islands”, the Sembelan Islands. This is the most common fact about this beautiful part of the Andaman Sea.

Did you know there is more to the naming of the Similans than just them being named after the Yawi word for the Number “nine”?

The fishermen would travel along the Malay Peninsula, between Malaysia and Burma; this will have been a busy thoroughfare back when borders were not so strictly defined. Undoubtedly they would have encountered the nomadic sea gypsies, also known as Moken, along their way.

Fishing in the Nine Islands

Fishing the Similan Islands in former times

A Moken village on the nearby Surin Islands

The Moken hold many fascinating tales, legends and campfire stories about their existence in the Andaman Sea. The Similan Islands feature in one of the central stories to their folklore, the epic poem of Gaman the Malay. This is a masterpiece of Moken oral history and the one which has given the momad society its cultural identity. Koh Bon and Koh Tachai, also in the Similan National Park, are well documented in this story too.

It’s also interesting to note that the Moken refer to the islands as the Seway Islands, not surprisingly this means number 9 in the Moken language.

In the past, during the successful reign of the East India Company and back when Great Britian had a very strong bond with what was then known as “Siam”, the British Navy would refer to the Similans as the Seway Islands. When you search for the Seway Islands on the internet nowadays, you will be taken to maps of the Similans.

Even today the Moken still inhabit the coastline and islands from as far south as Phuket, travelling through the Similans to the Surin Marine National Parks and up to as far north as the Mergui Archipelago in Myanmar. Their stories of the Similans hold many secrets from the past, however, when searching for information about the islands it is not these interesting tales that you will readily find.

Diva Andaman in the Similan Islands

An old fashioned style Similan liveaboard, reminiscent of a bygone age


One of the most fascinating pieces of information about the Similan Islands is the fact that these granite rock formations are so incredibly old.

It is astonishing to learn that this intriguing landscape was formed more than 250 million years ago in the Paleozoic period, a time even before dinosaurs roamed the earth. This was an important period in our planet’s geological past. It was a time when the marine environment was dramatically changing, when fish, amphibians and reptiles were evolving. The landscape was changing and it’s inhabitants were developing accordingly.

Ancient granite boulders in the Similan Islands

Imagine a time 250 million years ago…The Similan Islands

The Similan Islands are formed of granitoids, bodies of rock formed by cooled magma. Their appearance is unusual and striking, completely unique.

As they have been slowly weathered over the years, these fascinating rocky outcrops are now suspended above and below the Andaman Sea along the coast of Burma and Thailand.

A much more detailed geology of the Similans can be found here.

It is easy to see this landscape as timeless: when sitting on a Similan liveaboard of an evening, staring out at the beautiful rock formations sat in the Andaman Sea, it is possible to completely lose track of time.

The Similans are a place for ultimate relaxation and stunning natural beauty.


The varied forest systems that are present here and the huge array of both land and marine plant and animal species make this an intriguing and visually breathtaking place to see.

The mammoth boulders that characterise the Similan Islands are just one aspect of this slice of Thailand that is a must see destination. The Islands are an ideal and easy-to-reach destination for dive safaris, sailing and snorkelling trips. They are even perfect for hiking and birdwatching.

The immense diversity of the islands and marine sites guarantee that each and every visitor has an unforgettable experience both above and below the surface of the water. Welcome to the Similans!


Although the dinosaurs are long gone since the time the Similan Islands were formed, the sea surrounding the islands is still home to giants of around the same era. Whale sharks and Giant manta rays, a relatively newcomer to the scene at just 50 million years in existence, migrate through the marine national park heading north towards Burmese waters or south down the Malay peninsula.

Ancient reptiles can still be found on the islands themselves. Monitor lizards are frequently seen. They can grow to an impressive size of 3 metres and resemble the famous Komodo Dragons found in Indonesia.

As well as the large life that you might be lucky enough to see on the Similans, there are also the smaller critters than clamber across the sand or flit between the trees such as chicken crabs and a vast variety of birdlife.

Much more information about the wildlife to be discovered in the Similans can found here.

Ancient reptiles like this Monitor lizard seen in the Similan Islands


Similan Islands at a Glance
Name: Mu Koh Similan National Park Map of the Similan Islands with names
Location: Phang Nga Province, Andaman Sea, Thailand
Founded: 1982
Area: 140 km² (80,000 Rai)
No. of Islands: 9 + 2
Season: October 15 to May 15
Weather: North Eastern Monsoon.
Activities: Scuba Diving, Snorkelling, Sailing, Camping, Bird Watching, Kayaking
Accommodation: At present overnight stays on the Similan Islands is prohibited
Wildlife: Similan Islands Nature and Wildlife Guide
Geology: Similan Islands Geology Guide
Fees : 500 THB general admission + 200 THB per day per diving guest


When you can visit the Similan Islands is strictly controlled by the Marine National Park and the Royal Thai Navy. The Similan Islands are open from mid October to mid May and closed mid May to mid October.

The actual dates vary slightly year to year. For the 2019-2020 Similan diving season the National Park will open on the and will likely close around

Perfect conditions at the Similan Islands

Perfect Andaman Sea conditions, blue skies and tourquoise waters

When you can go to the Similan Islands is essentially controlled by the annual monsoons that govern Thailand’s weather and climate. Khao Lak’s high season and when the national park is open coincides with the north-east monsoon, November to April. The wind blows across Thailand from China, bringing with it cooler and dryer air. Off shore winds make for more perfect Andaman Sea conditions.

From May to October the weather and climate is controlled by the south-west monsoon. South-westerly winds bring hot, humid air from the Indian Ocean which in turn bring clouds, heavy rainfall and can make for unsafe sea conditions. The Similan National Park close the islands for these six months to give the natural resources time for rehabilitation. Visiting the islands during this time is not only highly dangerous, the Royal Thai Navy strictly enforce the closed policy.

The annual monsoons play a large role in determining the conditions at the Similan Islands. There are also other considerations, especially for scuba divers in planning the best time to visit the Similans, including tides and water visibility.


Similan Islands location

Many roads lead to Khao Lak, the main point of departure to the Similan Islands. Here is where the adventure begins! From Khao Lak it is short journey to your waiting boat at Thap Lamu Pier. Divers and snorkelers will usually be picked up at their Khao Lak accommodation, or meet at the dive centre, for a group taxi ride to Thap Lamu.

Similan Islands, How to Get There at a Glance
National Park HQ: Situated on the road to Thap Lamu pier, 14 km south of Khao Lak, 4 km off Highway 4
Thap Lamu Pier: 500 m past National Park HQ
From Bangkok: Daily flights to Phuket or Krabi Town with Bangkok Airways, Thai Airways and Air Asia, then taxi or bus to Khao Lak, taxi to Thap Lamu Pier
From Phuket: Taxi, mini-van or hourly bus service leaving Phuket Town to Khao Lak, then taxi to Thap Lamu Pier
From Krabi: Taxi, mini-van or hourly bus service departs Krabi Town to Khao Lak, then taxi to Thap Lamu Pier

Similan diving safari boats also depart to the Similans directly from Phuket, or provide a direct taxi transfer from Phuket to Thap Lamu. Thailand Dive & Sail will gladly advise you of your exact itinerary and best options for travel.


The Similan Islands are also home to some of the most interesting and diverse dive sites in Thailand, making it a number one spot for scuba divers who visit the land of smiles. A top holiday destination, Khao Lak is ideally located for visitors wishing to combine relaxation, Thailand’s well renowned hospitality and an activity packed trip diving at the best dive sites.

There are a number of different options for those wanting to explore the turquoise waters of the Andaman Sea, just off the coast. Whether you are looking for a quick diving fix, a slightly longer overnight trip out to the islands or an extended diving liveaboard, there is something for everyone.

The first type of diving trip that we would recommend to any scuba fanatics visiting Thailand would be a Similan liveaboard. This really is the best way to explore all that the Similan Islands have to offer as you have an extended stay within the marine national park and without lengthy daily transfers. Waking up next to a tropical island and getting straight into the water is a special experience, and one that you will only have on an overnight trip or liveaboard safari.

Relaxing on a Similan liveaboard

Relaxing on a Similan liveaboard

Abundant fish life at Koh Tachai Dive Site in the Similans

Visit the better sites on a Similan liveaboard

This option also gives you the opportunity to take in more of the better dive sites that are situated to further north, Koh Tachai and Richelieu Rock. There is such a variety of marine flora and fauna here that one day is just not enough to experience it all. More detailed and the latest updated info about Similan liveaboards can be found here.

If you have only a few days in Khao Lak then an overnight trip is also a good option. On a 2 day 1 night, or better still – a 2 day 2 night trip, you will get the chance to get more dives in (typically 6 or 7) and will wake up at the dive sites.

Usually the shorter overnight trips focus on one area of the Similans; this may be the Similans only, or it might incorporate Koh Tachai, Koh Bon and Richelieu Rock. Either way you will get the chance to expand your dive log and fit 3 day trip’s worth of dives into 2 days – meaning only 2 transfers instead of 6.

For those that really are short of time on their holiday, or those popping into Thailand for a mini break (many people do!), then the diving day trip is the best option to maximise your time and fit in some diving too. As previously stated, Khao Lak is ideally located for diving in the Similans, it’s proximity to the dive sites means that it is the best place as a departure point for day trips.

A day trip will be via speedboat or catamaran and will involve approximately and hour and a half trip there and back. The Islands that you will visit may be limited, due to the distances travelled. Day trip options include days dedicated to the Similans, Richelieu Rock, Koh Tachai or Koh Bon, or you can try a combine trip to Koh Tachai and Koh Bon on the same day.

Which ever type of trip you choose to visit the Similan Islands, you will not be disappointed. This beautiful part of Thailand is one of the main reason why people visit Khao Lak, and if you choose to venture out there, you will see why for yourself.

Whale Shark at Richelieu Rock

January to April can be sensational diving at the Similan Islands

For more information about diving in the Similans read our Similan Diving Guide or check out our latest news about last season’s sensational diving in the Similan Islands.

Similan Scuba Diving at a Glance
Season: 15 October – 15 May
Best time to go: January – March
Experience: Suitable for all levels
Water Temperature: 29-30˚C average surface water temperature
Visibility: 12 – 40 meters
Tides/Currents: Weak to moderate; stronger at full and black moon
Salinity: 30 – 33% per thousand
Depths: 0 – 50 meters /dives generally limited to maximum 30 meters
Types of Sites: Fringing, sloping reefs; granite and limestone rock pinnacles; boulder and hard coral reef gardens. To view our Dive-Site Guide, click here
First Aid: All dive-staff trained in emergency first response, first aid and secondary care; all boats carry 100% emergency medical oxygen; evacuation plans in place; doctor stationed at Island #4
Recompression Located at Bangkok Hospital Phuket; representative based in Khao Lak. Thai Government Hospital Chamber located in Thap Lamu.
Fees: In addition to the 500 THB general admission fee, diving guests will be charged 200 THB per diving day
Training: SSI and PADI
Nitrox: See our list of dive operators offering Nitrox

The conditions in the Similans are usually close to perfect during high season, however, this is not always the case. For basic information about Similan weather and sea conditions please read more here.


Similan Islands Elephant Head Rock

With a great array of different dive-sites, and of course many different ways to dive each of them, the Similans are so diverse that visitors return again and again, each time discovering something new.

From soaring underwater rock pinnacles to flourishing hard and soft coral garden reefs to giant boulder formations and swim-throughs, the dive terrain is unique at each dive-site.

Marine life indigenous to this particular area of Southeast Asia abounds, with sightings of rare species, both large and small, common.

The underwater world of the Similans provides a myriad of subjects for the passionate photographer, both macro and wide-angle.

Click on the dive site name for a more detailed individual description:

Similan Dive Sites
Christmas Point Similan Islands Dive Sites
North Point
Breakfast Bend
Turtle Rock
Beacon Reef
Elephant Head Rock
Deep Six
West of Eden
East of Eden
Anita’s Reef
Hideaway Bay
Honeymoon Bay
Shark Fin Reef
Boulder City


Three absolutely fantastic dive-sites lie a short journey north and northeast of the Similans:€“ Koh Bon, famous for frequent Manta Ray sightings and it’s awesome limestone wall and pinnacles; Koh Tachai, popular for its vast plateau, fringing granite rock formations and leopard sharks; and world-class Richelieu Rock, a huge, breathtaking horseshoe-formation just breaking the surface of the water, home to abundant rare marine life and stunning, soft purple coral gardens and sea fans.

These dive sites are reached most conveniently on a liveaboard, please refer to Similan Liveaboards how to best reach them and the Similan Islands in one go.

Mu Koh Similan National Park was extended in 1998 to include the two northerly islands of Koh Tachai and Koh Bon, while Richelieu is such an unforgettable and nearby dive-site that all three of these attractions are usually included in most every live-aboard trip to the Similans. Day-trips to both Koh Bon and Richelieu Rock are also available. No dive-safari to the Similans is complete without a visit these sites.

Click on the dive site name for a more detailed individual description:

Similan Islands Koh Bon
North Similan Dive Sites
Koh Bon Ridge north similan dive sites
Koh Bon Pinnacle
Koh Tachai
Richelieu Rock


An exceptional and safe opportunity to discover the underwater world for the non-diver. The coastlines near the beaches of the Similan Islands are studded with beautiful bommies, coral gardens and rock formations at shallow depths, allowing for a birds-eye view over the expansive seascape. Swim with turtles and mantas, skin-dive amongst schools of tropical fish and perhaps even follow the divers at sites far below the surface. Experienced professionals on every boat are there to guide you for your safety.

Please click here for Thailand Dive and Sail’s complete Similan snorkelling day trip and overnight options as well as private charter trips and snorkelling at Koh Tachai and undiscovered Koh Prathong.

Snorkelling with a turtle in the Similan Islands
Similan Snorkelling at a Glance
Season: 15 October – 15 May.
Best time to go: January – March.
Experience: Suitable for all levels.
Water Temperature: 29-30˚C average surface water temperature.
Visibility: 12 – 40 meters.
Tides/Currents: Weak to moderate; stronger at full and black moon.
Recommended Sites: Anita’s Reef, Hideaway Bay,Beacon Beach and Reef, Breakfast Bend, East of Eden, Koh Bon Ridge, North Point to Christmas Point, Princess Bay. For maps of these snorkel spots please see our dive-site guide.
First Aid: All dive-staff trained in emergency first response, first aid and secondary care; all boats carry 100% emergency medical oxygen; evacuation plans in place; doctor stationed at Island #4.
Equipment: Buoyancy jackets, mask, snorkel and fins in all sizes are provided by your boat operator. You may prefer to bring your own.
Fees: 500 THB general admission fee.
Clothing: A swimsuit is sufficient, though we recommend more sun protection in the form of a long-sleeved rashguard, t-shirt and shorts.
Protection: Please make sure to wear high-spf sunscreen while snorkeling, ideally all over, but pay attention to the back side of your body, as the sun will be shining directly onto you. Don’t forget to protect your neck, ears, back, thighs, shoulders, upper arms, etc.! We cannot stress this point enough.
Contact Lenses: If you wear lenses, please bring a spare set just in case you lose one.
Wildlife: Similan Islands Nature and Wildlife Guide
Note: Island #1, #2 and #3 are Royal Thai Navy marine reserves and turtle breeding grounds! While snorkeling is permitted, access to the beaches is strictly prohibited.


Experience the beauty of the Similans on your own sail boat! For individuals, groups and families of sailing enthusiasts, the islands are the ideal tropical destination and stunning basis for extensive diving, snorkeling and island exploration. Moor in stunning bays and enjoy the peace and relaxation of a remote, uninhabited island atmosphere. Adventure on your own time and at your own pace in an environmentally-friendly manner. Let us charter your sail boat, skipper and crew to the Similans, arrange diving and snorkeling gear and customize your independent sailing trip itinerary.

We are able to recommend and book charters with or without crew, as well as introduce you to experienced freelance dive staff and guides to accompany you on your adventure. If you are sailing independently throughout the local area on your own boat, please feel free to contact us regarding marine conditions, equipment and insightful tips and information about sailing the islands. Diving and snorkeling sites are listed in our Similan Island Diving Guide / Snorkeling Guide. Please also refer to Similans Islands at a Glance, as well as our Wildlife Page.

Similan Islands Sailing at a Glance
Moorings: Always available in picturesque, sheltered spots around the islands and in the bays. To protect the environment, please DO NOT drop anchor in the Similans or Surins, but use the moorings provided.
Water: Non-potable water sources available on Island #8. Fresh drinking water is not available in the Similans, please make sure to stock bottled water!
Provisions: Can be arranged by Thailand Dive & Sail.
Food: Small, simple restaurant on Island #4 and Island #8.
Refuse: Please do NOT dispose of any garbage or non-biodegradable items on the islands or in surrounding waters. Take it back with you. Large bins and dumpsters are available at the main piers in Phuket, Thap Lamu and Khuraburi for disposal..
Waste: Please do not empty holding tanks or bio-degradable items in the vicinity of the islands.
Pets: Domesticated animals are not allowed in the National Park. If you have house pets with you on your own boat, please leave them on board.
Flags: All marine vessels are required to fly a Thai flag when sailing Thai waters.
Immigration: Ranong, Phang Nga and Phuket provide immigration checkpoints and stamp-in for around-the-world travelers. Advance arrangements may be made via Thailand Dive & Sail.
Diving: If you are certified, equipment rental available via Thailand Dive & Sail, dive boats in the vicinity offer air and Nitrox filling service for approximately 200 THB per tank, some may also provide a guide. Please see our Similan Island Dive Guide
Snorkeling: Unlimited. Please see our Snokeling Guide for recommended sites.
Wildlife: Similan Islands Nature and Wildlife Guide
Note: Island #1, #2 and #3 are Royal Thai Navy marine reserves and turtle breeding grounds! While snorkeling is permitted, access to the beaches is strictly prohibited.


There are currently no options for overnight stays on the Similan Islands. The only way to experience the Similans overnight is from a Similan liveaboard. Spending a 4 day 4 night trip on board floating accommodation is the ultimate way to see the islands and wake up next to some spectacular views. Most liveaboards moor near the islands at night, meaning that sunset and sunrise have awesome backdrops.