Similan Islands 2026: New Diving and Snorkelling Rules You Need to Know

The Similans Are Open — With New Regulations

The Similan Islands, a chain of eleven granite islands about 70 kilometres off the Phang Nga coast, are widely regarded as one of the best diving and snorkelling destinations in Thailand. The national park opened for the 2025-2026 season on October 15, 2025, and will remain open until May 15, 2026. After that date, the park closes entirely for the monsoon, allowing marine life to recover.

This season, Thailand's Ministry of Natural Resources and Environment has introduced several significant new rules that apply across all marine national parks, including the Similans. These regulations were published in the Royal Gazette and are now actively enforced.

New Snorkelling Rules

The biggest change affects snorkellers. All snorkellers are now required to wear a buoyancy aid at all times while in the water, unless they hold a valid scuba diving or freediving certification. The rule is designed to prevent accidental coral damage from swimmers who lose buoyancy control and stand on or kick the reef.

Tour operators departing from Khao Lak and Phuket have adjusted their equipment packs accordingly. If you book a snorkelling day trip, a life vest or inflatable snorkel vest will be provided as standard.

New Camera Restrictions for Divers

Underwater cameras are now restricted to experienced divers only. To use a camera underwater in the Similan Islands, you must hold an Advanced certification (PADI, SSI, RAID, or equivalent) or above, or have at least 40 verified logged dives. Cameras are not permitted during training dives unless a dedicated photographer has been assigned by the operator.

The reasoning is straightforward: inexperienced divers with cameras tend to focus on their screens rather than their buoyancy, increasing the risk of fin strikes on coral. Similar coral protection rules have also been introduced at Koh Tao, another of Thailand's premier dive destinations.

Visitor Limits Still in Place

The national park continues to enforce daily visitor caps. The number of divers and snorkellers allowed into the park each day is limited, so booking in advance is strongly recommended during high season months from December through April. Liveaboard trips, which typically run three to five nights, also book out weeks ahead.

What to Expect Underwater

The Similans are famous for crystal-clear visibility often exceeding 25 metres, manta ray encounters at sites like Koh Bon and Richelieu Rock, and dramatic underwater granite boulder formations. Water temperatures range from 27 to 30 degrees Celsius, so a 3mm wetsuit is sufficient. Above the surface, the islands also rank among the most beautiful beaches in Thailand and are perfect for kayaking and paddleboarding between dive sessions.

How to Get There

Most visitors depart from Khao Lak, about a 90-minute drive north of Phuket Airport. Speedboat day trips take roughly 70 minutes to reach the islands. Liveaboard boats depart from Tab Lamu Pier in Khao Lak and cover a wider range of dive sites over multiple days. If you are planning a longer trip to the region, the Phi Phi Islands and Koh Lipe are both reachable from the Andaman coast and worth combining with a Similans trip.

Plan Your Visit

With the park closing on May 15, the window for the current season is narrowing. If the Similans are on your list, book soon — the combination of visitor caps and peak-season demand means last-minute spots are hard to find. Make sure you have travel insurance in place before departure, and check the Thailand Digital Arrival Card requirements if you are flying in from abroad. A solid eSIM or local SIM card will also keep you connected for last-minute bookings while on the road. For those flying into the region from Singapore, it is also worth noting that Singapore Airlines is exploring a new nonstop route to northern Thailand which could simplify connections for travellers routing through Changi.