The Similan Islands are a chain of granite islands far out in the Andaman Sea, northwest of Phuket. Giant smooth boulders, powder-white sand and very clear blue water make them look quite different from the limestone islands closer to Phuket. They are also a protected national park that is only open for part of the year. This guide explains where the Similans are, how to get there, when the park is open and what a day there looks like.
Where are the Similan Islands?
The Similans lie off the coast of Phang Nga province, roughly 70 km west of Khao Lak. They form Mu Ko Similan National Park. The main chain is numbered from south to north, and the park also includes Koh Bon and Koh Tachai further north. The name comes from the Malay word for nine, after the original nine islands.
Two islands see most day visitors:
- Koh Miang (Island No. 4) has the park office, a long beach and forest trails.
- Koh Similan (Island No. 8) is the largest island and home to Donald Duck Bay (Ao Kuerk) and Sail Rock, the granite boulder with the famous viewpoint.
Other islands in the chain are used for snorkeling stops. Which ones your boat visits depends on the park rules for that season and on sea conditions.
How to get there from Phuket
Day trips leave from piers near Khao Lak, most often Thap Lamu. From Phuket, a day trip usually means:
- An early hotel pickup and a road transfer north to the pier, often around 1.5 to 2 hours depending on where you stay.
- A speedboat crossing of around 1 to 1.5 hours to the islands.
- Several stops for snorkeling and beaches, with lunch on one of the islands.
- The same journey in reverse, back at your hotel in the evening.
It is a long day, and the crossing is on open sea. If you get seasick easily, read is the boat ride to the Similans rough first. Staying a night in Khao Lak before the trip shortens the morning a lot. Liveaboard dive boats also visit the Similans on multi-day trips.
Note: we do not currently sell a Similan Islands trip. If you want a calm snorkeling day from Phuket instead, look at Racha and Coral Island or Phi Phi and Khai Island.
When is the Similan national park open?
The park closes every year during the southwest monsoon, when the sea is too rough for safe crossings and the reef gets a rest. In most years it opens around 15 October and closes around 15 May. The exact dates are announced by the Department of National Parks and can move with the weather, so check before you plan around them. Individual islands or dive sites can also be closed for recovery.
Within the season:
- October to November: seas can still be lively after the monsoon, but boats are less crowded.
- December to March: usually the calmest seas and best visibility. This is also the busiest period.
- April to mid-May: hot and often still good, with conditions becoming less reliable towards the closing date.
The park also limits how many visitors can go each day, so book ahead in peak season. See when do the Similan Islands open and close.
What to see and do
Snorkeling
The Similans are known for clear water and healthy reefs. On a snorkeling day you can often see reef fish, giant clams and colorful hard and soft corals. Sea turtles are sometimes spotted too. Sightings are never guaranteed. Our Similan snorkeling guide goes deeper.
Donald Duck Bay and Sail Rock
On Island No. 8, a short but steep climb up the boulders near Donald Duck Bay leads to the viewpoint beside Sail Rock. From the top you look down over the curved bay and the boats below. Wear shoes with grip and go slowly: the rocks are smooth and there are ropes and steps in places.
Beaches
The sand on the Similans is fine and bright white, and the water is shallow and clear close to shore. Koh Miang's long beach is one of the best places to relax between snorkeling stops.
Diving
For certified divers, the Similans are one of Thailand's best known dive areas, with granite boulders, swim-throughs and reef slopes. Dive trips are organized separately from standard snorkel day trips.
Practical tips
- National park fee: the Similans are a national park, so a fee applies to every visitor. Many day trips include it, but check. Our park fees guide lists the current rates.
- Passport: bring your passport or a copy. Park entry can require identification.
- Sunscreen: bring reef-safe sunscreen or a rash guard. Sunscreens with certain chemicals, such as oxybenzone, are banned in Thai marine national parks.
- Food and plastic: the park has strict rules on litter and single-use plastic. Take everything back to the boat.
- Pickup time: expect a very early start if you are staying in the south of Phuket.
- Weather: trips can be cancelled on rough days even in season. Keep a spare day in your plans.
Respect the reef
The Similan reefs are protected because they are fragile. Many areas are marked with buoys to keep boats off the coral.
- Do not touch, stand on or kick coral. Wear a life jacket if you need to rest.
- Keep a respectful distance from turtles and never chase or touch them.
- Do not feed fish.
- Do not take shells, sand or coral. Removing them is illegal in the park.
Similan or somewhere closer?
The Similans are worth the long day for strong swimmers and anyone who cares most about clear water and reefs. If you have young children, get seasick easily or are visiting between mid-May and mid-October, a closer island is a better choice. Racha Island has some of the clearest water near Phuket and is open all year. We compare other remote options in Similan vs Surin and island tours from Khao Lak.
Frequently asked questions
When are the Similan Islands open?
Usually from around 15 October to 15 May. The park closes during the southwest monsoon. Exact dates are set each year by the national park authority.
How long does it take to get to the Similans from Phuket?
Plan on a full day. It is usually around 1.5 to 2 hours by road to the pier near Khao Lak, then around 1 to 1.5 hours by speedboat.
Can I stay overnight on the Similan Islands?
Overnight stays on the islands have been restricted in recent seasons. Most visitors come on day trips or on liveaboard dive boats. Check the current park rules if you want to stay.
Are the Similan Islands good for non-swimmers?
Non-swimmers can snorkel with a life jacket in calm conditions, but the long open-sea crossing makes the Similans better suited to confident travelers. Closer islands are easier.
Do you offer a Similan tour?
Not at the moment. See our current tours from Phuket for snorkeling and island days that run all year.
