Similan Islands
Eleven granite islands with some of the clearest water in Thailand and the best diving in the country.
The Similan Islands are 11 granite islands 70km west of Khao Lak, part of a national marine park. Day trips from Khao Lak cost from 3,200 baht; liveaboards run three to five days. The park closes from mid-May to mid-October.
Open Similan Islands in Google Maps8.6500, 97.6500
Park fee THB 500; e-ticket with passport number required since October 2025
Entry fee checked against operator or park publication, October 2026. Hours can change without notice — confirm on the day.
Eleven granite islands with some of the clearest water in Thailand and the best diving in the country.
The islands are granite rather than limestone, which is why they look different from the rest of southern Thailand — smooth boulders piled into arches and balanced rocks above white sand. The reef around them is one of the best in Thailand, with visibility up to 30 metres, and Richelieu Rock to the north is one of the world's top dive sites for whale sharks. Over 100,000 visitors a year forced a daily cap of 3,325 and a four-month annual closure.
The granite boulders, white sand and visibility of 30 metres are the reason people fly around the world to dive here. It is a national park, closed May to October.
What you’ll actually see
- Donald Duck Bay on Koh Similan with its boulder viewpoint over the anchorage
- The reef at Koh Bon, where manta rays are regularly seen from December to April
- Richelieu Rock, a submerged pinnacle covered in soft coral and fusiliers
- The beach at Koh Mieng, where sea turtles nest between November and February
How to visit it well
- Day trips from Khao Lak take 90 minutes each way; a liveaboard is better value.
- The park closes annually — check opening dates.
- No drones without a permit.
Mistakes worth avoiding
- Coming in the monsoon season — the park is closed from mid-May to mid-October
- Booking the cheapest speedboat that visits four islands in six hours
- Touching or standing on coral; the park fines for it
Is it worth it?
Worth the money and the best diving and snorkelling in Thailand. A day trip is good; a liveaboard is far better because you get Koh Bon and Richelieu Rock, which day boats cannot reach. Book three months ahead in high season.
Common questions
Mid-October to mid-May. The park closes for the monsoon and for reef recovery the rest of the year.
From about 3,200 baht per person including speedboat, lunch, park fee and hotel transfers from Khao Lak. Liveaboards run from 18,000 baht for three days.
There is basic tent and bungalow accommodation at Koh Miang, booked through the national park. Most visitors do day trips or liveaboards.
Both. The snorkelling at Koh Ba Ngu and Koh Similan is excellent; the diving at Koh Bon and Richelieu Rock is world class.
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Last updated: October 2026 · Prices and hours checked by Nattapong Srisuwan