When Do Similan Islands Open and Close?
Seasonal Access to the Similan Islands
Unlike most tourist destinations that are accessible year round, the Similan Islands have a strict opening and closing schedule tied to the monsoon season. Understanding this schedule is essential for anyone planning a Phuket trip with the Similans on their list.
When Do They Open?
The Similan Islands typically open around October 15 to November 1 each year. The exact date is announced by the Department of National Parks (DNP) and can vary by a week or two depending on weather conditions. The DNP assesses sea conditions, checks that park infrastructure is ready after the monsoon, and then sets the official opening date.
When Do They Close?
The islands close around May 15 each year. Again, the exact date varies slightly. Sometimes the closure is extended if monsoon conditions arrive early. Once closed, no tourist boats are permitted to visit the islands until the following season.
Why Do They Close?
The closure is driven by two factors:
Safety
During the southwest monsoon (May to October), the Andaman Sea in the Similan area experiences:
- Wave heights of 2 to 4+ meters
- Strong currents
- Reduced visibility
- Unpredictable weather with sudden storms
These conditions make speedboat crossings to the islands dangerous. Even the journey from Tap Lamu Pier to the islands (60 to 70 minutes in good conditions) can become life-threatening in monsoon swells.
Conservation
The annual closure gives the marine ecosystem a 5-month rest from human activity. During this time:
- Coral reefs recover from any tourism-related stress
- Marine species breed and feed without disturbance
- Beaches regenerate naturally
- Park rangers conduct ecological surveys and maintenance
This seasonal rest is a major reason why the Similan Islands maintain such healthy reefs compared to year-round destinations that never get a break from tourism.
Best Time Within the Season
The season runs roughly 7 months (mid-October to mid-May), but conditions vary within that window:
October to November (Early Season)
The sea may still be slightly rough from the tail end of monsoon. Some days are excellent, others less so. Fewer tourists mean smaller tour groups and less crowded islands. Prices may be slightly lower.
December to February (Peak Season)
The best overall conditions. Calm seas, maximum visibility (often 25 to 30 meters), minimal rain. This is also the busiest period. Tours fill up quickly and should be booked at least a few days in advance, if not earlier.
March to April (Late Peak)
Still excellent conditions, though temperatures are higher (it can feel very hot on the islands). Visibility remains good. Slightly fewer crowds than December to February.
May (End of Season)
Conditions begin to deteriorate as monsoon approaches. Some days are fine, others see rough seas. There is a small risk of tour cancellations due to weather. The islands typically close in the second or third week of May.
Planning Around the Season
If Similans Are a Priority
Plan your Phuket trip for January through March for the best combination of weather and availability. Book your Similan tour as early as possible after confirming your travel dates.
If You Visit During Monsoon Season
The Similan Islands will be closed and there is no way to visit. Alternative snorkeling options during monsoon include:
- Koh Racha: Accessible year round with good snorkeling
- Coral Island: Short crossing, calm water, basic snorkeling
- Phi Phi Islands: Tours run during monsoon but may be cancelled on rough days
For more on monsoon travel, see our rainy season tours guide.
How to Check Current Status
The most reliable way to check whether the Similan Islands are currently open:
- Contact your tour operator directly
- Check the Mu Ko Similan National Park social media pages
- Ask your hotel's tour desk
- Contact us and we can confirm current status for your dates
Important Notes
- No overnight stays: Camping and overnight visits on the Similan Islands have been suspended indefinitely to support conservation. All visits are day trips only.
- Daily visitor limits: The park has caps on daily visitors. During peak season, tours can sell out. Book ahead.
- Weather cancellations: Even during the open season, individual tour departures may be cancelled due to rough conditions. Book with operators that offer free rescheduling or refunds for weather cancellations.
The seasonal closure of the Similan Islands is both a limitation and a gift. It means you need to plan your visit within a specific window, but it also ensures that when you do visit, the reefs and marine life are in the best possible condition. That trade-off is why the Similans remain one of the world's great snorkeling destinations. Browse our available tours to check Similan Islands availability for your dates.
