Located off the southern coast of Thailand, in the Andaman Sea, diving in the Similan islands is a fun, exciting adventure for people of all abilities.
While there are many places to scuba dive in Thailand, diving in the Similan Islands is not to be missed. If possible, try to plan a trip to this small outcrop of land in the middle of the sea for it will be an experience you won’t want to pass up.

Geography
The Similan Islands are eleven different islands, named Ko Bon, Ko Bayu, Ko Similan, Ko Payu, Ko Miang (two adjoining islands), Ko Payan, Ko Payang, and Ko Huyong and the recently added Ko Bon and Ko Tachai. Because there are so many, the islands are referred to in number, starting at 1 in the south and ending at 11 in the north.
All of the islands are part of a national park which covers 140 square kilometres in total. 14 of the square miles refer to the Similan Islands themselves.

The islands are about 50 kilometres from the coast of Thailand, with the nearest mainland town being Khao Lak. The land was made from hot magma that came to the surface over 65 million years ago. The rock has since been smoothed down by glacial ice and the tides of the sea. About 5000 years ago, coral reefs formed around the magma rocks, making them the oldest in all of Thailand.
Although the 2004 tsunami hit the area hard, thankfully the islands and the coral reef were relatively undamaged, thanks to the fact that the water is quite deep in the area, which protected everything.
Over time, sediment and dirt has found its way to the tops of the rock islands, and as a result they are covered in tropical jungle. There are even some beaches with bright white sand.
Marine Life
Diving around the Similan Islands is considered one of the best places in the world, and once you swim underwater you’ll know why. The waters are filled with a rich diversity of fish species. There are lionfish and clownfish galore. The waters are also home to manta rays and whale sharks.
On Koh Huyong there is a turtle breeding facility and as a result, access to that island is restricted.
While there is an abundance of sea life, what makes diving in the Similan Islands the best is that the waters are crystal clear. Whatever is swimming, you will be able to see. Unfortunately, one aspect of diving that is negative is that in 2010 the coral has fallen victim to coral bleaching. It is recovering, but it is a slow process.
Other Animals
In addition to the diverse sea life, the Similan islands are also home to a number of on land animals. There are the famous Nicobar pigeons as well as flying foxes.


The islands are home to a number of laying hen chicks, so be careful where you step so as to avoid disturbing their nests.
Specific Islands
While all diving trips will take you past all of the islands, they do vary in their landscape and types of animals that inhabit them.
Koh Similan is the largest island and features a large bay called Horseshoe Bay. The water is quite shallow and better for snorkelling rather than scuba diving. Its sand is often compared to white flour. Next to the bay is a towering rock formation that you can climb, and it provides a stunning view of the islands.
Koh Pa Yu has shallow and deep water diving and is often the most preferred location of scuba divers. The east side has a hard coral reef and a soft coral reef, allowing for different fish species to make themselves at home. There is also a coral mound on the north side. The island is all rock and has no beach.
Koh Miang has large rocks on its island but soft corals and plenty of fish in the water. There are a number of ducks that make their home here.
Koh Ba Ngu has a fantasy mount complex that is filled with soft corals and sea fans. Scuba diving is best of the northeast coast of this island.
Koh Bon has larger sea creatures including barracudas, sharks, batfish and manta rays.
Best time to Visit Similan Islands
Before you plan your vacation to the Similan Islands, make sure they are actually open. The high season is between December and April because the rainy monsoons to not make an appearance. From May 16 to November 15, the national park is closed.
Travel Starting Points
There are a number of places that you can start your journey to the Similan Islands from. From these different places you can book a dive trip. Trips are usually four days and four nights but can be longer or shorter, depending on demand. To enter the national park, it costs 500 baht per person plus 200 baht per diver per day. Most tours do not include these fees in their package prices.
While trips may say they are from Phuket, it is actually the Phuket area, so be sure to pay attention to the specific location of departure. Departure points could be from Chalong, Patong or even Tap Lamu. Most trips will offer pickups from major beaches.
While smaller than Phuket, Khao Lak is the mainland town closest to the Similan Islands. There are a number of dive centers in the town that offer trips. There are also a few places that offer dive trips from Koh Lanta, which is further south than Phuket.
Where to Sleep
Because most divers book sleep and stay trips, most likely the boat is where you’ll be sleeping. If, however, you’ve taken your own boat to the islands, there are a few options. Tents and bungalows are available to rent through the National Park headquarters in Tab Lamu, or if you’re LUCKY through specialty agents. Bungalows can only be found on Koh Miang and tents can be found on Koh Miang and Koh Similan.
Diving in the Similan Islands is a great experience. Clear blue waters are home to an abundance of sea life and no matter what your diving experience, it is an opportunity not to be missed.