In short
- Park is open from October 15 to May 15.
- February to April offers the calmest seas.
- No access is permitted from May 16 to October 14.
In this article
You cannot visit the archipelago year-round. Thailand closes the park every rainy season to allow coral reefs to recover and to protect boats from rough seas. If you want to snorkel here, you need to time your trip right.
When is the Similan Islands best time to visit?
The ideal time for a day trip is from February to April.
During these months, you get the calmest seas and the highest underwater visibility. This makes the 70 to 90-minute speedboat ride from Khao Lak much smoother. High visibility is crucial since snorkeling is the main activity here.
What are the exact opening dates?
The park opens on October 15 and closes on May 15 every year.
These dates are strictly enforced by the Department of National Parks. The marine park operates from 08:00 to 16:00 daily during the open season. You cannot enter the park outside of these dates or hours.
| Status | Dates |
|---|---|
| Open | October 15 to May 15 |
| Closed | May 16 to October 14 |
Why is the park closed half the year?
Thailand closes the area to let marine ecosystems recover and to avoid monsoon storms.
From May 16 to October 14, the Andaman Sea experiences heavy rains and large waves. It is not safe for passenger speedboats to make the 65 to 70-kilometer crossing from Thap Lamu Pier. The closure also gives nature a break from the daily cap of 3,850 visitors.
How is the weather early in the season?
October and November can still see occasional rain and choppy water.
While the park is open, the transition out of the monsoon season takes time. Boat rides might be bumpier. If you are prone to seasickness, you should choose a power catamaran tour or wait until the weather settles in December.
Is there a bad time to visit during the open season?
Peak holiday weeks are the busiest times on the islands.
Late December and January draw maximum crowds. The national park limits entry to 3,850 people per day, but primary mooring points will feel full. Always book your tour well in advance if you travel during these peak weeks.
How do park fees work during the season?
Foreign adults pay 500 THB and children pay 250 THB.
This mandatory national park fee applies every day the park is open. Most group tours cost between 2,800 and 4,500 THB from Khao Lak. Prices change, but this usually includes your entry fee. Verify this before booking.
Questions travellers ask
Are the Similan Islands open all year?
No. The national park is strictly closed to all visitors from May 16 to October 14 annually.
When is the best time to visit the Similan Islands?
February to April is the best time to visit. The sea is calm, and the water is clear for snorkeling.
How long is the boat ride to the Similan Islands?
The speedboat ride takes 70 to 90 minutes from Khao Lak. If you start in Phuket, add 1.5 to 2 hours for the overland transfer.
