You come over the last of the swell and the water simply stops being a colour you have a word for. Granite boulders the size of houses tumble into a bay so clear the boat looks like it is hanging in air, and above them a single wedge of rock leans out over the Andaman like a sail. The Similans are seventy kilometres from anywhere, open only seven months of the year, closed to overnight visitors entirely, and capped at a few thousand people a day — which is precisely why, standing on that beach with the forest behind you and nothing but blue in front, it still feels like something the world has not quite got around to spoiling.
What the Similan Islands are
Eleven granite islands in the Andaman Sea
Mu Ko Similan National Park protects a chain of eleven islands roughly 70 kilometres off the coast of Phang Nga, north of Phuket. The name comes from the Yawi (Patani Malay) word for nine, from the original count before two northern islands were added to the park. What makes them distinctive is the rock: huge rounded granite boulders piled along the shorelines and continuing underwater, forming swim-throughs and canyons quite unlike the limestone karst scenery further south. The sand between them is white and unusually fine, and the water is clear enough to see the bottom from the boat.
Closed for five months of every year
The park shuts completely from mid-May to mid-October under an order from Thailand's Department of National Parks, covering both Mu Ko Similan and neighbouring Mu Ko Surin. The closure is partly about the southwest monsoon making the crossing dangerous, and partly about giving the reefs a recovery period without visitors. It is absolute — there is no reduced service and no exceptions for liveaboards. The reopening date is confirmed by the department only shortly beforehand, so early-season bookings carry real uncertainty.
A hard cap on how many people land each day
Even in season, access is limited. A daily visitor cap has been upheld in the Thai courts, and overnight stays on the islands were banned in 2018, so the park is now day trips and liveaboards only. Certain sites are managed more tightly still: Koh Tachai's beach has been closed to landings for years, and although operators sometimes imply otherwise, its reopening has not been confirmed. These are not soft guidelines — they are the reason the islands still look the way the photographs promise.
In-depth guides
Practical, independently checked guides to planning your visit — written from the source, not recycled from other listings.
When the Similan Islands Open and Close
Mu Ko Similan is shut by law for five months a year. The season runs 15 October to 15 May — here is why, and what it means for booking.
Read the full visitor guide → Fees and ticketsSimilan Park Fees and the DNP E-Ticket
Foreign adults pay 500 THB, children 250 THB. Since October 2025 the ticket must be bought online with a passport number.
Read the full visitor guide → Park rulesThe 3,850 Daily Cap and Similan's Park Rules
Similan limits visitors to 3,850 a day and bans overnight stays, single-use plastics and reef-toxic sunscreen.
Read the full visitor guide → The islandsWhich Similan Islands You Can Land On
Eleven numbered islands, but only two you can walk on. Koh Miang, Koh Similan, the closed turtle islands, Koh Bon and Koh Tachai.
Read the full visitor guide → In the waterSnorkelling, Diving and Similan Liveaboards
Day-trip snorkelling, scuba day trips and multi-night liveaboards reach different parts of the park. Which matches what you want to see.
Read the full visitor guide → Where to startSimilan Day Trips: Khao Lak vs Phuket
Everyone boards the same boats at Thap Lamu. Starting from Phuket adds a long van transfer at both ends — here is what that costs you.
Read the full visitor guide → Getting thereSpeedboat or Catamaran to the Similans?
Seventy kilometres of open Andaman Sea, twice in a day. The difference between the two boats is mostly about your stomach.
Read the full visitor guide → TimingThe Best Months to Visit the Similan Islands
The park is open seven months, but they are not equal. Visibility, sea state, marine life and crowds all shift between October and May.
Read the full visitor guide →Frequently asked questions
When are the Similan Islands open?
The park's season runs from 15 October to 15 May. Thailand's Department of National Parks closes Mu Ko Similan and neighbouring Mu Ko Surin for about five months each year for monsoon safety and reef recovery — the 2026 closure was announced as 15 May to 15 October. No operator can legally run trips during the closure, and the exact reopening date is confirmed shortly before mid-October.
How much is the Similan national park entrance fee?
Under the fee schedule effective 7 June 2022, foreign adults pay 500 baht and foreign children aged three to fourteen pay 250 baht. Thai adults pay 100 baht and Thai children 50. Scuba divers pay a supplement, commonly applied at 200 baht per diver per day. Many tour prices exclude the park fee and collect it at the pier — always check the inclusions.
Do I need to book a park ticket in advance?
Yes. Since the 2025–26 season opened on 15 October 2025, an e-ticket from the DNP system has been mandatory, bought through the QueQ app or the department's website. Foreign visitors must supply a passport number; tickets are non-transferable and non-refundable. Same-day purchase closes at 08:00. Most operators handle this, but they need your passenger details in advance.
Can I stay overnight on the Similan Islands?
No. In 2018 the Department of National Parks closed all accommodation — thirty-five bungalows and two campgrounds on Ko Miang that had housed up to 190 people a night — citing waste and sewage pressure on a small remote island. There are no hotels and no camping anywhere in the archipelago. The only legitimate way to sleep in the park is aboard a liveaboard moored offshore.
Is Richelieu Rock part of the Similan Islands?
No. Richelieu Rock sits in Mu Ko Surin National Park, roughly 18 kilometres east of Ko Surin Tai and around a hundred kilometres north of the Similans. It appears on Similan liveaboard itineraries because those boats continue north into Surin waters. If Richelieu is your reason for booking, confirm the itinerary includes Surin, and expect a separate national park fee.