The Similan Islands are a line of granite islands in the open sea about 70 km west of Khao Lak, protected as Mu Ko Similan National Park. Smooth boulders the size of houses, blinding white sand and water with visibility that can pass 30 metres make them the benchmark for snorkelling and diving in Thailand. The islands are known by number as well as by name, from No. 1 in the south to No. 9 in the north; the park also includes Koh Bon and Koh Tachai.
The park is closed every year during the south-west monsoon — roughly mid-May to mid-October — and when open it limits the number of visitors per day. Day trips and liveaboards therefore need booking ahead in peak season.
Top things to do: Similan Islands
Sail Rock and Donald Duck Bay
Island No. 8 (Koh Similan) has the park’s emblem: a boulder balanced above a horseshoe bay. A short scramble leads to the viewpoint. The beach on island No. 4 (Koh Miang) is the other main landing.
Snorkel
Day trips make two or three snorkelling stops over coral and boulders. Green and hawksbill turtles are regularly seen. Conditions are generally at their calmest and clearest from about February to April.
Dive by liveaboard
Multi-day liveaboards from Khao Lak cover the Similans, Koh Bon, Koh Tachai and usually Richelieu Rock. Manta rays are seen most often around Koh Bon; whale sharks are occasional and never guaranteed.
How to get to Similan Islands
- From Khao Lak: speedboats leave Thap Lamu Pier and take around 1.5 hours. This is the closest base.
- From Phuket: the same boats, with a road transfer of about 1.5–2 hours each way to Thap Lamu — a long day.
- There are no scheduled ferries; you visit on an organised day trip or a liveaboard.
Insider tips
- The park fee is around 500 baht for foreign adults, with an additional daily fee for divers. Some tours include it; many collect it in cash.
- Overnight stays on the islands have not been permitted in recent years, so a liveaboard is the only way to stay in the park.
- The crossing can be bumpy. Take seasickness tablets beforehand, and sit at the back of the boat.
- Parts of the park, including some turtle-nesting islands, are closed to visitors. Opening dates and quotas are set each season — check before booking.
Best tours & tickets for Similan Islands
These well-reviewed experiences are the easiest way to see Similan Islands:
Speedboat snorkelling trip from €108 Similan Islands Early-Bird Tour from Phuket and Khao Lak
The best-reviewed way to see the Similans in a day. An early boat from Thap Lamu pier gets you onto the beaches and reefs before most groups arrive. Runs only while the park is open, roughly mid-October to mid-May.
- Three snorkelling stops in the national park
- Sail Rock viewpoint on island No. 8
- Hotel transfers from Phuket or Khao Lak
