The Similan Islands

Why people come to Khao Lak at all

The Similans are the reason this stretch of coast has a tourist economy: nine granite islands about 60 km offshore, with water clarity that regularly reaches 20–30 metres and beaches of coarse white boulder-sand. Khao Lak is the nearest mainland base, which is why day boats leave from here and not from Phuket alone.

What a day trip looks like: pickup from your hotel early morning, speedboat from Thap Lamu, two or three snorkelling or beach stops — typically around Ko Miang (island four, the park headquarters) and Ko Similan itself — and back by late afternoon.

What is closed: Koh Tachai, the northernmost island, has been closed to visitors since 2016 for reef recovery, and overnight stays on the islands are banned. Divers who want more than a day go by liveaboard instead.

The daily limit, and why to book ahead

Since 2018 the park has capped how many people may visit each day. In 2024 Thai PBS reported the limit as 3,325 visitors a day, plus 525 places for scuba divers, split between the two islands boats land on, Ko Miang and Ko Similan. Tour operators hold the places, so in the busiest weeks, Christmas to New Year above all, day trips can sell out. Book a few days ahead in peak season rather than on the morning.

The same order ended overnight stays. Older guides describe camping and bungalows on Ko Miang; neither is available any more, and a tour selling a night on the islands is selling something the park does not allow.

Koh Tachai: closed, and what that means for your tour

Koh Tachai was closed in May 2016 after anchors and crowds damaged its reef. In September 2024 Phang Nga officials and the park said they were considering reopening it to a limited number of visitors, with set swimming areas and no anchoring on coral, but no reopening date had been announced by 2025. Until the park announces one, a day trip that promises to land on Koh Tachai is out of date. Dive boats can still dive the pinnacle offshore; see the diving guide.

Before you go

Bring reef-safe sunscreen. Since August 2021 Thailand has banned sunscreens containing oxybenzone, octinoxate, 4-methylbenzylidene camphor or butylparaben in all its marine national parks, with fines of up to ฿100,000. Mineral sunscreen labelled non-nano zinc oxide or titanium dioxide is the safe choice, and a rash vest needs no sunscreen at all.

Check whether your tour price includes the national park fee. Many quote it separately, and it is paid per person on top. Expect a long day: hotel pickups start early, and the speedboat crossing from Thap Lamu takes an hour or more each way.

We cover hotels along this coast — the Khao Lak beaches, Phuket and Krabi — plus a handful on Koh Samui, across in the Gulf. Start with hotels in Khao Lak, or browse every hotel we cover; prices and availability show on the partner's own site.

Planning the rest of the trip? Compare places to stay, or see what is open month by month.