Diving in the Similan Islands is one of Thailand's most popular excursions. With such incredible scuba diving sites on offer, it's not hard to understand why. Similan Island SCUBA diving is largely dictated by its ferocious volcanic history, created by upsurges of molten-hot magma over 65 million years ago. Glacial ice then covered the entire area, eroding and smoothing the jagged, peaked landscape. Some 5,000 years ago, the first reef systems appeared after the glacial ice retreated, and have since grown and evolved into some of the best scuba diving sites in Asia. Diving in the Similan Islands has been made into an awe-inspiring adventure thanks to its tumultuous geological history.
The Similan Islands are located in the Andaman Sea, Thailand around 84 km northwest of Phuket. The area is a designated Marine National Park, Mu Koh Similan. Established in 1982, the national park status has greatly helped to restrict illegal and destructive activities that previously threatened the natural beauty of the islands. However, now, the Similan Islands are producing some of the most prolific dive spots in Thailand, all thanks to the incredible efforts of the local communities.
Similan Islands scuba diving is characterised by two main categories of site, those that lie to the east, and those to the west. Prevailing currents, moving from west to east, have created a strong distinction between these sites. Scuba diving locations to the west are rocky, with large granite boulders that have remained exposed and free from sedimentation due to strong, "spin-cycle" currents. Here you will find a whole host of fascinating features of swim-throughs, ledges, and cavern zones, all attracting a wide assortment of marine life. Some of the most notable sites include Boulder City, and Deep 6. To the east you will be scuba diving over gently sloping coral reefs, with the occasional boulder still visible but most are now buried under sand. The most famous site here is called East of Eden.
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Marine life in the Similan Islands
Marine life on the dive sites of the Similan Islands is truly abundant. Over 200 species of hard corals have been counted here, painting the fields of boulders in stunningly vibrant colours. To the east, coral gardens are found in as little as 16 feet (5 m) of water making for excellent beginner scuba diving spots and even snorkelling sites. Large table corals and staghorn corals attract shoals of snapper and black damsels. To the west, many larger species can be seen, including oceanic whitetip and blacktip reef sharks, leopard sharks, and barracuda, while Whale sharks and manta rays provide the cherry on top. In between rock crevices, moray eels lie in wait, while overhangs and ledges provide shelter for several species including triggerfish, unicornfish and surgeonfish.
Best dive sites in the Similan Islands
Boulder City lies 1 km off the east coast of Koh Payan, and it is also subject to fairly strong currents. Some very large granite boulders sit upon a sandy bottom, forming chains of submerged boulders. This site is frequently visited by manta rays, and even whale sharks, attracted by the plankton carried by strong currents. Soft corals grow in patches on the boulders, and are home to numerous macro species including nudibranchs.
Elephant Head Rock is a greatly enjoyable dive site with various tunnels and swim-throughs. This is quite a deep site, reaching a maximum depth of 165 feet (50 m), and where you will find leopard and oceanic whitetip sharks. Mantis shrimps can be found at deeper depths, while both hawksbill and olive ridley sea turtles usually remain in shallower areas.
Best time to dive in the Similan Islands
Scuba diving season lasts from November to early May for most liveaboards that operate here, the warmest months being February and May. Water temperatures are 84 Fahrenheit (29C) at their warmest, dropping to 79 Fahrenheit (26C) during rainy season. Visibility remains a very clear 65 to 130 feet (20 to 40 m) throughout the year, while currents are at their strongest during February. This creates some fantastic drift dives while also attracting very big pelagic species.
Experience level for diving the Similan Islands
To gain the fullest experience diving in the Similan Islands, it is recommended that scuba divers have a little more experience. These islands are classed as intermediate to advanced because of the exposed nature of dive sites to the west.
How do I get to the Similan Islands
Thailand liveaboard vessels offer divers great access to teh Similan Island and will usually depart from either Phuket of Khao Lak. The best way to reach Khao Lak is to drive along the beautiful coastal road from Phuket International Airport. Many liveaboards will arrange a vehicle to pick you up directly from the airport, but it is also possible to rent a car or catch a shuttle bus. The journey is relatively short, taking no more than 2 hours and usually around an hour and a half.
Many international services are now available direct to Phuket Airport, although most long-haul flights will require a connection. Bangkok is usually where most connecting flights are caught, but depending on where you initially departed, it is possible to fly through Hong Kong, Singapore or Sydney.