Best Diving in Similan Islands

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The Similan Islands offer super bio-diversity of marine species co-existing in colorful coral gardens and impressive rock seascapes.

Red colored Thailand Jewel Grouper, Orange Anemone Fish, Yellowback Anthias, Green Sea Turtles, Blue Surgeon Fish, Indigo and Violet soft corals… these are just standard rainbow colors to start with.

National Geographic, CNN Travel, List25, these are just a few sources which consider the Similan Islands to be among the best diving destinations of the World.


The Similan National Park is situated in the Andaman Sea, northwest of Phuket.

The Similan Islands are a group of 11 islands forming an archipelago which occupies an area of 70 km² (27 mi²).

Mergui Archipelago

Mergui Archipelago (Myanmar) is another largely unexplored dive destination located within 180 km (100 nautical miles) to the northwest of the Similan Islands. You might want to consider the idea of joining a liveaboard dive safari which covers that destination in addition to the Surin & Similan Islands.

Diving Review

Diving at Similan National Park is only allowed from October to May due to the monsoon season. This is due to the fact that the monsoon brings heavy rains, winds, and waves between June and September.

The Similan group of Islands features about 25 dive sites. If you have enough time and would like to explore the best of the Similans, choosing a liveaboard option is the best option. In addition, the average price per dive becomes more reasonable on a 3 days or more liveaboard trip. Note that boats going for only 1-2 day trips might be overcrowded.

Best dive sites overview

Koh Tachai, Koh Bon, and Richelieu Rock are the most thrilling dive sites usually accessible by liveaboard. They give a possibility to get acquainted with the diverse flora and fauna of the Similan Islands.

Koh Tachai

That multi-level dive site is one of the best at Similan Islands. Manta Ray and Whale Shark are frequent guests over the seascape of different corals and granite rocks. Leopard sharks, Schools of Barracudas, Snappers, Trumpetfish, Pufferfish, Triggerfish, Sweetlips, Groupers, Tunas, and Sea Snakes are some of the residents of the place. You might encounter medium and strong currents which can change during the same dive. That is why the site is recommended for advanced divers. The average depth is about 15-18m (49-59ft.) with the maximum depth of 30m (98 ft.)

Koh Bon

The dive site is recommended for advanced divers because of the medium and strong currents. You never know whether Manta Ray or Whale Shark is to visit the area at the same time with you, so you’d better plan that dive site for the afternoon.  The sun will give the best light at that part of the day to study a wall full of Sea Fans, soft corals, Anemones, Shrimps, Morays, Lobsters, and Nudibranchs. The dive site is great for underwater photography. The average depth is about 15m (49 ft.); the maximum depth is 30m (98 ft.).

Richelieu Rock

Richelieu Rock belongs to Surin National Marine Park but most of Similan liveaboards visit this dive site. How can they miss a chance to see a Whale Shark, Manta Ray, and Leopard Shark among the big ones and a great variety of Boxfish, Groupers, Cuttlefish, Pineapple Fish, Barracuda, Tuna, and Leopard Morays? Do not rush over the corals; you’d better take a closer look in order to see Harlequin Shrimp, Seahorses, Porcelain Crabs, and Pipefish. The average depth of the dive is 8-15m (26-49 ft.).

West of Eden

This dive site is recommended for all divers. The average depth is about 10m (32 ft.). You can enjoy Hawksbill Turtles, Whitetip and Blacktip Reef Sharks passing by the large rocks, soft coral gardens, and Sea Fans. If you concentrate on micro life, you will have a chance to find Nudibranchs, Ghost Pipefish, Shrimps, as well as to enjoy clouds of Glassfish, Purple Firefish, and Goby.  Try to discover a Frogfish which is often found at this dive site.

Best dive season

The best time to dive the Similan Islands is at the end of March. Indeed, at that time of the year, the Andaman Sea is calm, warm and clear. You will have a chance to see Manta Rays who usually migrate from January to March and Whale Sharks who often visit the Islands between February and May. In addition, mainland accommodation prices usually drop toward the end of the diving season.

If you would like to see more Hawksbill Turtles you better come between November and February as it is their breeding season.

Visiting the Similan Islands during the Christmas/New Year Holidays might not be the best one. First of all, the Islands are overcrowded. Moreover, the Islands are usually closed to the public during the visits of the Thai Royal Family at the end of December or beginning of January. All Similan Tour Operators are usually advised about the exact days of the Royal Highnesses visits.

Dive conditions

Between November and February, the water temperature is 26-28ºC (78-82ºF); the average visibility is about 10-25m (32-82 ft.)

The water temperature starts to rise as of the end of February. It stays between 28-31ºC (82-87ºF). You can cool yourself down only in thermoclines of 25ºC (77ºF) at the depth of 15m (49 ft.). The visibility ranges between 15-30m (49-98 ft.).

If you are tortured whether to put on a shorty or a long wetsuit, give you preference to a 3mm wetsuit. It will better protect you from possible cuts on the coral reefs and rocks.

Night dives are really awesome at the Similan Islands. It’s a good idea to bring your own underwater dive torch and a backup light or flashlight if you have one. Daily boats and liveaboards provide torches with rechargeable batteries (limited battery life and power).

Marine life

The unique ecosystem of the Similan Islands features more than 500 types of corals and 3000 types of fish.

You can expect to see Whale Shark, Leopard Shark, Nurse Shark, Whitetip and Blacktip Reef Shark, and Grey Reef Shark. The Ray family is usually represented by Manta Ray, Eagle Ray, and Sting Ray. Reptiles are represented by Banded Sea Snake and Hawksbill Turtle.

The Similan Islands are famous for their microcosm, so you will have a chance to admire Harlequin Shrimp, Seahorses, Longnose Hawkfish, Nudibranchs, Porcelain Crabs, and Ghost Pipefish.

There are several islands where diving and land visits can be forbidden due to turtle preservation and coral regeneration programs. These are the Islands No.1 (Koh Huyong), No. 2 (Koh Payang) and No. 3 (Koh Payan).

Tsunami and Bleaching Situation

The seascape was protected and largely unaffected by the 2004 tsunami.

Since 2012, the cold water coming from the deep helped restore the coral growth after the 2010 coral bleaching which was due to the water temperature increase. Currently, the status of corals is good and you can enjoy Anemones, hard corals (Brain Coral, Staghorn Coral, Table Coral, and Mushroom Coral) and soft corals (Red Whip Coral, Black Coral, Sea Fan, Klunzingers Coral).

Park Entry Fees

Please take into consideration that you need to pay an entry fee of 500 THB (~14 USD) to Similan National Park and Surin National Park and a daily diving fee of 200 THB (~5 USD) per person.

The payment is usually made in cash to the boat operator. The operator then pays the Park Authorities.

For example, if you plan to dive one day at Richelieu Rock and another 6 days at Similan Islands, then you need to pay:  500 THB an entry fee to Surin National Park (to which Richelieu Rock belongs) + 500 THB an entry fee to Similan National Park + 200 THB x 7 diving days = 2400 THB (~68 USD).

Please be aware that there are fines and even imprisonment for violations of the Parks’ rules (such as taking any shells, corals, sand or even rocks).


The best option for you to explore Similan Islands is to join a liveaboard. Most of the liveaboards do not require some specific diving experience. However, it is much more comfortable for you to travel on a dive safari if you are at AOWD (Advanced Open Water Diver) or if you have at least 30 logged dives.

You might get lost seeing the number of operators providing boat services. Not all of the operators own licensed boats regulated by TAT (Tourist Authority of Thailand). It is safer to book a liveaboard via a 5 star PADI dive center in Khao Luk or Phuket. Among such dive centers, there are Thailand Liveaboards, Sunrise Divers, Similan Diving Safaris, Sea Dragon Divecenter, Wicked Diving, and iQ-Dive. You can also book a liveaboard through a global fleet operator like Aggressor Fleet or Manta Fleet.

Most of the boats depart from Khao Lak, Patong or Ranong. Usually, liveaboards offer a 4-7 nights stay. The price per day starts from 100 USD and goes up to 300 USD. Usually, it includes accommodation, 3-4 dives per day, meals, beverages, tanks, weights, and belts. The price normally excludes equipment rent and Park fees.

Mergui Archipelago Liveaboards

If you long for a less popular destination though with the same diversity of species under the water then try liveaboard to Mergui Archipelago (Burma). The main Similan liveaboards usually serve this destination. The boats start from Thailand coast.  This route is recommended for advanced divers due to stronger currents and longer trips.

Unlike in Thailand authorities of Mergui Archipelago request an entry fee payable in US Dollars. It is an amount of 200-250 USD per person which is to be paid in cash. You do not need to put a visa upfront, your dive operator will make all the necessary arrangements. However, it is recommended to take several copies of your passport pages and passport-size color photographs.

Top 10 liveaboards

Find below a selection of the top 10 Similan liveaboards.

Andaman Tritan

Andaman Tritan is 25m (82 ft.) long liveaboard and she can accommodate up to 16 guests. The cabins are distributed between the 3 decks. You will get all the needed comfort at a reasonable price.  The itinerary covers the main Similan dive destinations including the world famous Richelieu Rock.

Deep Andaman Queen

Deep Andaman Queen is one of the largest boats among liveaboards at the Similan Islands. She is 28m (91 ft.) long servicing up to 21 guests. The dive deck is very spacious. If you stay in Master Cabin you will have an opportunity to enjoy a great panoramic view. The boat offers different itineraries in the Similan Islands, Surin Islands, and the Mergui Archipelago.

Diva Andaman

Diva Andaman is a luxury 35 m (114 ft.) long sailing yacht. She can serve up to 14 guests. Besides standard liveaboard services, there are Thai massage, high cuisine, and wine cellars onboard. Don’t be upset if sail goes up just a few times. The rare deck is rather tiny; all dives are made from a Zodiac.

DiveRace Class E

A new 34m (111 ft.) long yacht can accommodate up to 20 guests in her 10 cabins. There is plenty of space on board including a salon, a massage room, and a sundeck. The crew consists of 15 people to help you during your diving vacation. The itinerary covers the Similan Islands, the Richelieu Rock dive site, and the Mergui Archipelago.


Hallelujah is a big boat with the length of 35m (114 ft.). She is ready to accommodate up to 25 guests in 13 cabins. She normally starts her trips from Thap Lamu upon picking up the guests from Phuket or Khao Lak; it is included in the price. If you are a single traveler you might be pleased to know that there is a VIP single cabin on the very top of the boat. The itinerary includes the main Similan attractions.


Giamani is a 24m (78 ft.) long boat based in Phuket. She serves up to 10 guests who can be accommodated in 1 Master and 4 Deluxe cabins. There will be enough space for the guests to relax in the 2 decks with a library and a sundeck. The itinerary covers the main Similan dive sites.

The Junk

The Junk is a real movie star after participation in the James Bond’s “The Man with the Golden Gun”! She is an old charming sailing yacht of 33m (108 ft.). But sail will not be up all the days. The yacht can accommodate up to 18 guests. The quality of services is superb. There is no traditional dive deck and all the dives are made from Zodiacs. The itinerary covers the main Similan dive sites.


Pawara is a spacious 35m (114 ft.) long vessel. There are 11 cabins on the boat to accommodate 24 guests. A huge lounge is located on the upper deck. There are 2 twin cabins on the lower deck which you can choose as a budget option if you do not mind to share bathrooms. Pawara is based in Phuket, but transfers from Khao Lak are also available. The route includes the main Similan diving destinations.

Thailand Aggressor

A 35m (115 ft.) long yacht is part of the luxury Aggressor Fleet. She serves up to 16 passengers. There is a large sun deck, Jacuzzi hot tub, bar, and grill. The dives are made from 2 Zodiacs, each of them can accommodate up to 9 divers. Thailand Aggressor visits such dive sites as Richelieu Rock, Koh Bon, Koh Tachai, Elephant Head, and West & East of Eden. Usually, the boat departs on Saturdays and it provides 7-night trips. There is a possibility to go on the other itinerary around the Mergui Archipelago.

White Manta Thailand

White Manta is a 36m (118 ft.) long vessel. She is part of the Manta Fleet. This liveaboard can take onboard up to 24 passengers in her 12 cabins. There are 2 Zodiacs to reach the most interesting diving sites of the Similan Islands and Richelieu Rock. The meals are served 5 times a day, so you will not get hungry. You can also enjoy a relaxing massage after a dive right on the boat.

Other activities for non-divers


If you take a day boat tour, you will most likely have a chance to visit 2-3 sites for snorkeling.

One of the places for a lunch will be Honeymoon Bay, Princess Bay or Donald Duck Bay. While snorkeling, you can enjoy wonderful coral reef inhabitants in the shallow waters. However, do not forget to look into the deeper waters as Manta Ray, Eagle Ray, Leopard Shark, Turtle or even Whale Shark might be passing by!

How to get there

There is no airport on the Islands that is why the only way to reach the Park is by the sea. So it is a good idea to choose Phuket as a starting point.

Most likely your liveaboard will depart from Thap Lamu Port in Khao Lak.  Some boats use Thai Muang and Rassada Pier near Phuket, so you’d better check with your boat operator.

If you book in advance, an operator or a dive club will organize a pick-up from your accommodation. You can also use a bus, a taxi or a mini-van to get to Khao Lak.

In case wish to travel to Khao Lak straight from Phuket Airport, the transfer will take about 1 hour. A transfer from the Port to the Islands usually takes from 45 min up to 3 hours depending on the boat.

Travel tips

Feeling inspired and raring to go? Check out our Similan Islands travel guide and start planning your next diving trip!

Dive Sites Reviews in Similan Islands

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Liveaboard Reviews in Similan Islands

Been diving here with a liveaboard? Please share your experience using the comment section!
janice February 03, 2017

Been diving on the Dolphin Queen, Liveaboard in the Similan Islands. Not the first time i joined those guys for a trip. Coming here every year again and I just loove it! Amazing diving, amazing food, amazing boat, amazing company! Best choice in the Similans!


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