Similan Islands: when to go, how to get there, dive or snorkel?

What are the Similan Islands?

A marine national park of eleven islands off Phang Nga province.

Mu Koh Similan National Park is made up of nine islands numbered from south to north, from Koh Huyong (island 1) to Koh Bangu (island 9), plus Koh Bon and Koh Tachai, which were added later. There are no villages and no hotels: just the park office, a few trails and white-sand beaches. On the west side, huge granite boulders drop into deep, clear water; on the east side, coral reefs form gentle slopes that are ideal for snorkelling.

When are the Similan Islands open?

From 15 October to 15 May every year, without exception.

The park closes during the southwest monsoon, when the swell makes the crossing dangerous, and to let the reefs recover. In the first and last weeks of the season the sea can still be rough, so December to April, the calmest stretch, is the safer bet.

To fit this into the rest of your trip, see when to go to Thailand.

Day trip or liveaboard?

Two very different ways to see the same islands.

A speedboat day trip packs in three or four snorkelling stops and one or two beaches, plus lunch. Check whether the park fee is included: many Khao Lak operators include it, but not all. On a liveaboard you dive three or four times a day, early in the morning before the day boats arrive, and reach Koh Bon, Koh Tachai and Richelieu Rock, which are out of range for day trips.

The best dive and snorkelling sites

The east side for snorkelling, the west side and the north for diving.

Hard corals have suffered from bleaching in recent years, especially in the shallows: these days the park’s reputation rests on its granite boulders, its visibility and the big animals passing through.

What about Koh Tachai?

The park’s most beautiful island is still closed to visitors.

Koh Tachai was closed in 2016 to let its beach and reefs recover from overcrowding. No reopening date has been announced, so a tour promising to land there is not a serious one. Liveaboards do, however, dive its underwater sites, such as Tachai Pinnacle, known for its schools of fish and leopard sharks.

What level do you need to dive the Similans?

There is something for every level, as long as you pick the right sites.

Currents can be strong on the points and northern pinnacles: guides plan the dive order around the tide, and most boats ask you to carry a surface marker buoy. If you have not dived for more than a year, book a refresher in Khao Lak or on the first day of the trip.

Park fee, visitor cap and rules

The park limits visitor numbers and does not allow overnight stays on the islands.

The entrance fee is 500 THB per foreign adult and 250 THB per child aged 3 to 14, with an extra fee of around 200 THB per day for divers. Daily visitor numbers are capped: in high season operators book their slots in advance, which is a good reason to book your trip a few days ahead rather than the night before.

• No regular sunscreen in the water: choose an oxybenzone-free one, or wear a rash guard.
• Do not stand on coral or feed the fish.
• Single-use plastic bags and bottles are banned in the park, so bring a refillable bottle.
• Overnight stays on the islands have ended: the only way to sleep there is aboard a liveaboard.

How do you get to the Similan Islands?

Everything leaves from Thap Lamu pier, just south of Khao Lak.

The speedboat takes about 1 hour 15 minutes from Thap Lamu to the islands. Tours pick you up at your Khao Lak hotel around 7 am and drop you back around 5 pm. From Phuket, add about two hours by minibus each way: it works, but a night in Khao Lak makes the day far more enjoyable.

Khao Lak is around 1.5 hours by road from Phuket airport. Our Khao Lak guide covers its beaches and areas, and the Phuket guide helps if you are choosing between the two bases.

What does a speedboat day trip look like?

A full day, with a good part of it spent in the water.

1. 1Hotel pickup around 7 am, light breakfast at Thap Lamu pier.
2. 2A crossing of around 1 hour 15 minutes, then the first snorkelling stop on an eastern reef.
3. 3Donald Duck Bay and the climb to Sail Rock for the view.
4. 4Lunch on Koh Miang, then two afternoon snorkelling stops.
5. 5Back at the pier around 4 pm, at your hotel around 5 pm.

Are the Similans worth it?

Yes for the water and what lies beneath it, less so if you want a quiet beach at noon.

In high season, Donald Duck Bay has several hundred visitors at once between 11 am and 2 pm: the beach is anything but secluded. What makes the day is what you see underwater, and the colour of the water itself. If you want a quiet beach, stay on an inhabited island instead: see our pick of the best beaches in Thailand and the Thai islands.

For divers there is no question: the Similans and Richelieu Rock are the country’s top diving destination, and the main reason to come to Khao Lak.