Similan Islands Set to Close for the Low Season 2025

The Similan Islands, a desirable destination nestled within the Andaman Sea, is among Thailand’s most popular tourist spots. The islands are best known for their dazzling marine life, untouched beaches, and top-tier dive sites, they draw nature lovers and underwater adventurers from around the globe. However, given the islands’ immense popularity it is essential that it is given a well-deserved break, and therefore, come May every year, Similan Island is shut for conservational reasons.

From late next week –  May 15, 2025 until October 15, 2025, the Similan Islands National Park will be closed to all visitors. Though this may alter your travel plans, this seasonal closure plays a key role in conserving the islands complex ecosystems.

A Seasonal Sanctuary

Much like in previous years, the Similan Islands shut their gates as the monsoon season rolls in. From mid-May to mid-October, heavy rains and rough seas make the region less accessible and more dangerous.

However the rest and relaxation that the Similan Islands is afforded, is not solely for weather-related reasons, it’s a deliberate break that allows the region and its substantial marine life to recover from the mass entry of visitors seen during high season. In this case, it is very much like that which occurs at Maya Bay – an equally popular destination within the Phuket region that needs to be preserved.

We’ll now walk you through the key reasons why Thai officials are determined to continue the low season closure of the Similan Islands:

Protecting Marine Life

The closure plays a big part in the preservation of aquatic life. Many colourful fish species, manta rays, whale sharks and so much more call the Similan Islands home. Regular tourism, even when managed well by considerate boat operators, places pressure on these habitats.

With no boats, snorkelers, or divers in sight for six months, the marine environment is allowed to rest. Coral can regenerate, fish return to less trafficked waters, and sea turtles have a chance to nest in peace. This yearly obligation to the Andaman Sea is essential in order to protecting the region for future generations.

Rejuvenation of Vegetation

Despite the focus on rejuvenating the marine life that calls the Similan Island home, it’s not just the ocean that benefits from the closure. On the island’s beaches, and trails, with a significant reduction in foot traffic, nature is able to prosper. Without the many thousands of people leaving their footprints on the island, vegetation is able to flourish, new wildlife emerges, and the ecosystem of the islands can reset. All of this not only helps Mother Earth to reset but creates the most natural experience when the island reopens in October.

Maximizing Visitor Safety

While preservation is key, the safety of visitors is also a central reason behind the seasonal closure of the Similan Islands.

Safety is also a key reason behind the seasonal closure. Anyone familiar to the region will attest that the Andaman Sea can be extremely unpredictable and dangerous throughout the monsoon season, highlighted by strong winds and currents that create high waves and treacherous conditions for boat trips. Closing the Similan islands during this period is a way to ensure that visitors are able to enjoy the islands at their most prosperous time, when conditions are calm and safest.

What To Expect When the Similan Islands Reopen

When the Similan Islands reopen on October 15, 2025, visitors will be greeted with a rejuvenated environment that will feature revitalized marine life, lush vegetation and idyllic beaches. Upon re-opening the daily visitor numbers will be capped at 3,850 to assist in limiting the human impact and preserving the natural beauty of the region during the open season.

What to expect:

• Coral Reefs Full of Life
• Crystal Clear Waters
• Lush Vegetation
• Rejuvenated Diving Spots

Minimizing Your Impact Upon Reopening

To help preserve the Similan Islands, every traveller can play their part Here are a few easy (light) steps you can take on your visit to the island:

• Avoid touching or standing on coral.
• Keep a safe and respectful distance from all marine life
• Clean up after yourself – don’t litter and take all rubbish with your or place into bins
• Stick to the beaten paths – don’t deviate into bushland
• Support boat tour operators that follow park guidelines and engage in sustainable practices

Does Simba Visit the Similan Islands?

Simba Sea Trips, as one of the most respected and responsible boat tour operators, offers Similan Islands tours during the high season (from October 15th through May 14th annually). A Simba tour is well-known for earlier departures from most standard tour operators therefore ensuring that we are there before the vast majority of crowds. With small groups, we ensure a more personalised and relaxed tour. It’s the best choice for those looking to enjoy the islands in ultimate comfort!

Summing Up

While the closure of the Similan Islands may be less than ideal for those thinking of visiting the region during the low season, it’s essential that the closures keep taking place to ensure the long-term viability of the region. For those venturing to Phuket in the high season then planning ahead and booking your tour today will make sure that you don’t miss out on a seat when the islands re-open. And make no mistake, its a region well worth seeing upon reopening as they are guaranteed to be even more beautiful than before.

Trust in Simba Sea Trips to take you on a Phuket boat tour to one of Thailand’s most breathtaking destinations.