The Similan Islands comprise of 9 islands and in the National Marine Park, Koh Bon and Koh Tachai islands are also included. These 11 islands offers some 20+ official divesites.
( Similan Island # 1,2,3 are off limits to divers as they are protected for research with sea turtles laying eggs on the beaches.)
West Coast vs. East Coast
The west coast of the islands are totally exposed to the harsh weather during the off-season. This creates a very special diving environment and very different from the sheltered east side.
Large granite boulders cover the coast and plunge into the ocean, forming great rock formations with canyons, arch ways and swim throughs below the surface. Soft coral and sea fans thrive on some of the boulders adding colour and life to the sites.
It’s common for predatory fish like mackerel, trevallies and tuna to swoop in amongst the rocks and hunt. In the shallow part , 12-14 m., hard coral fields are widespread with grazing turtles and reef fish inhabitants. Currents can be a little bit trickier on the west side, but we use the massive boulders as shelter. Our favourites are West of Eden, Christmas Point and North Point.
The east coast of the islands are sheltered during the monsoon season, and the quieter waters allows long shallow sloping reefs to form.
The reef slopes down to about 18m, on the outside of the reef you’ll find sandy slopes with boulders and coral bommies spread out across the sand in the deeper parts.
Some of the reefs were damaged through coral bleaching during the El Nino phenomenon in 2010, especially in the really shallow waters, 10 m and above. Therefore we dive these sites a little deeper and differently nowadays then we did before. Now we are seeing corals coming back already since the previous season and it will be interesting to see how much they return this next monsoon season.
The outer islands
Koh Bon and Koh Tachai lies northeast of the Similan Islands, Koh Bon consists of limestone and Koh Tachai resembles the Similan Islands with granite boulders. Both islands are solitary surrounded by nothing but the sea.
They have a healthy population of resident reef life and are also visited by bigger animals like Manta Rays. We have seen them around both islands but especially Koh Bon since they have a few cleaning stations there.
Our most famous dive site, Richelieu Rock, isn’t actually a part of the Similan Island National Park, but is within the Surin National Park. It’s a massive horseshoe shaped pinnacle made of limestone in the middle of the ocean, teaming with marine life.
We have 3 wrecks in the local area, all worth visiting. MV Seachart 1, Bonsung Wreck and Prem Chai.
MV Seachart 1 is for advanced divers only since the top of the wreck is around 22m. But both the Bonsung Wreck and Prem Chai are easy accesible for all level of divers with a maximum depth of 20 m. They all lie on a sandy bottom with no nearby reef which makes them perfect as shelter, allowing mating and hunting for all sorts of marine life.