The Similan Islands are 84 kilometres northwest of Phuket, part of the Mu Ko Similan National Park, and consistently ranked among the top ten dive destinations in the world. They are accessible from Phuket between November and May — the park closes to visitors from mid-May to mid-October for conservation.
Here is an honest guide to what they offer and whether they belong in your Phuket itinerary.
The Similans have several qualities that combine to produce an underwater environment that is genuinely extraordinary. First, national park protection since 1982 has meant no industrial fishing, no anchoring on coral, and managed visitor numbers — the marine environment has had four decades to develop without sustained commercial impact. Second, the combination of granite boulder formations at depth — creating swim-throughs, overhangs, and caves — with healthy coral coverage and open-water visibility that regularly exceeds 30 metres. Third, the species diversity: whale sharks, manta rays, leopard sharks, hammerheads seasonally, barracuda schools, giant trevally, and more reef species than most divers see at any other single destination.
Richelieu Rock, technically a separate seamount north of the Similans, is widely cited as the best single dive site in Southeast Asia. Whale shark encounters here are regular enough that liveaboard operators specifically time trips around the season.
Divers, primarily. The snorkelling in the shallower areas around the islands is good, but the exceptional experiences are at depth and require diving certification. If diving is your priority activity in Phuket, the Similans should be at the top of your list. If you are thinking of doing an Open Water certification in Phuket partly to access the Similans, this is a reasonable plan — the conditions for learning to dive on Phuket’s near reefs are excellent.
The Similans are less appropriate as a casual day trip activity. The day trip from Phuket involves roughly four hours of boat travel (two hours each way) for time at the islands, which suits serious divers who want to maximise water time and is less ideal for a general beach and snorkel audience.
Day trips to the Similans run from Khao Lak, about 60 kilometres north of Phuket, which reduces the transfer time to around 90 minutes each way. From Phuket itself, the transfer to Khao Lak and then the crossing adds up.
Liveaboard trips — typically 3 to 5 nights sleeping on the boat, diving multiple sites per day — are the proper way to experience the Similans and what most serious divers choose. Several liveaboard operators depart from Phuket. The cost is significant but the experience is categorically different from a day trip.
The Similan Islands are a protected environment and the regulations are enforced. No touching coral, no anchoring, limited visitor numbers per day. The conservation model that has allowed the marine environment to reach its current quality is ongoing and depends on visitors respecting the rules that make it possible. If you are planning a visit, choose a dive operator that is a member of the Reef Check Thailand programme or similar conservation organisation.
— Captain Mark
Exceptional, uncrowded island day trips from Phuket. Family-owned and operated since 2004.
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