Mu Ko Ang Thong National Marine Park sits about 30km north-west of Koh Samui — a cluster of 42 limestone islands in the Gulf of Thailand, none of them permanently inhabited, all of them inside a protected national park that limits what you can do and where you can go. That restriction is the point. It is one of the few places in the Gulf that still looks the way it did before the resort developers arrived.
The short version
- How far: 1-1.5 hours by speedboat from Koh Samui; 2-2.5 hours by big boat
- Entry fee: ฿300 per adult, ฿150 per child aged 3-14 (foreigners); check whether your tour includes this or charges separately
- Big boat tour: typically ฿1,200-2,000 per person including lunch; slower, more passengers (50-70), fixed itinerary
- Speedboat tour: typically ฿1,800-2,800 per person; faster, smaller group (8-15), kayaking usually included
- Park closed: 1 November to approximately 15 December each year; reopening date varies by weather
- The main highlights: Emerald Lake (Talay Nai) on Koh Mae Ko; viewpoint climb on Koh Wua Talap; kayaking through the mangroves and sea caves
The 42 islands
The park covers around 102 square kilometres of sea and island, with only a handful of islands that boats actually stop at. Most are sheer limestone karst — the same geological formation you see in Phang Nga Bay and Ha Long Bay — rising straight from the water and covered in dense jungle. The colour contrast between the limestone, the tree cover, and the turquoise water is what the photos are trying to capture.
The two main destinations within the park are Koh Mae Ko (the Emerald Lake) and Koh Wua Talap (the viewpoint and park headquarters).
The Emerald Lake — Talay Nai
Talay Nai is a saltwater lake inside Koh Mae Ko, connected to the sea through an underwater cave. The water is a distinctive green-blue colour — the “emerald” name is justified, though the shade varies with the light and time of day.
Access involves a hike up and over a ridge — it takes 20-30 minutes each way and involves steep sections with rope assists. It is not difficult for reasonably fit adults, but it is not a stroll. The path can be slippery after rain. The view from the ridge is worth the effort regardless of whether you descend to the lake.
Note that swimming in Talay Nai is not permitted — the lake is protected. You can look, photograph, and enjoy the view.
Koh Wua Talap viewpoint
Koh Wua Talap is the largest island in the park and where the park headquarters is located. There is a beach here — usually the lunch stop for tours — and a marked trail up to the viewpoint at the island’s summit.
The viewpoint hike is about 30-40 minutes up on a rocky, sometimes steep path. What you get at the top is the panoramic view of the archipelago that appears in every Ang Thong photograph — limestone islands scattered across turquoise water as far as the horizon. The photo above was taken from this point.
Most tours visit both Koh Wua Talap and Koh Mae Ko. Budget your time accordingly: the two hikes plus lunch takes most of a full day.
Kayaking
Sea kayaking through Ang Thong’s channels and into the sea caves along the cliff bases is one of the best things to do in the park. The caves are accessible by kayak at high tide, and the rock formations visible from water level are different in character from anything you see on the viewpoint hike.
Most speedboat tours include kayaking in the price. Big boat tours sometimes include it, sometimes charge separately — check before you book. A kayak rental add-on typically runs ฿100-300 per person if not included.
Snorkelling
Snorkelling is available at designated spots within the park, usually around the base of limestone formations where there is coral and fish activity. Equipment is provided on most tours. Visibility depends on weather and season — best from January to April, more variable in the shoulder months.
The snorkelling at Ang Thong is good but not exceptional by regional standards. If snorkelling is your primary motivation, check whether activities closer to Koh Samui might suit better. Most people find the landscape and the hiking more memorable than the underwater visibility.
Tour types from Koh Samui
Big boat (catamaran or large ferry): the cheaper option. Prices typically run ฿1,200-2,000 per person including lunch and snorkelling equipment. You will be with 50-70 passengers on a fixed schedule. The journey takes 2-2.5 hours each way, which means more time at sea and less time on the islands. Suits budget travellers who want to see the park without spending heavily.
Speedboat (small group): typically ฿1,800-2,800 per person for a group of 8-15 people. The journey takes about 1-1.5 hours each way, leaving more time on the islands. Itinerary is slightly more flexible and kayaking is usually included. Suits those who want more out of the day.
Private charter: for groups wanting a fully private boat, prices start around ฿8,000-20,000 for the vessel, depending on size and operator. Check current rates with operators directly — prices vary considerably.
What is usually included: hotel pickup, return boat transfer, guided hike, snorkelling equipment, lunch. What is NOT always included: the ฿300 national park entry fee. Confirm when booking whether this is added at the pier or collected in advance.
Getting there from Koh Samui
Tours depart from piers on the north coast — typically Na Thon Pier or Ban Mae Nam Pier. Most operators include hotel pickup from major Koh Samui accommodation areas. If you are staying in Maenam or Bophut, you are closest to the departure points. Chaweng-based guests will have a 20-30 minute transfer to the pier.
Book via your accommodation or directly with tour operators. Avoid booking agents at airport arrivals — prices are higher.
The seasonal closure
This is the most important practical detail for trip planning: Ang Thong National Marine Park closes every year from 1 November to approximately 15 December. The exact reopening date varies by weather — the north-east monsoon that closes the park typically eases between December 10 and 20, but it can run longer.
If you are visiting Koh Samui in November or early December, you will not be able to visit Ang Thong. Plan accordingly. See the best time to visit Koh Samui guide for the full seasonal picture.
Practical advice
Start early. Tours depart at 8-8.30am for good reason — by midday, the main viewpoints and the Emerald Lake trail are at their busiest and hottest. Afternoon weather in the Gulf can deteriorate. The early start gives you the best light for photographs too.
Wear shoes with grip. Both the Koh Mae Ko trail and the Koh Wua Talap viewpoint hike involve rocky, sometimes loose footing. Flip-flops are not suitable. Lightweight trail shoes or grippy sandals work.
Bring cash. The park entry fee (if not pre-paid through your tour) is collected at the island. ATMs are not available on the islands.
Seasickness: the Gulf of Thailand is generally calm between December and April. In shoulder season (May-June, October), the crossing can be choppy, especially on speedboats. If you are susceptible to motion sickness, take medication before departure and choose a big boat if you need a steadier ride.
What to skip: the souvenir shops at the pier before departure are unremarkable and overpriced. Skip them.
Combining with Koh Phangan
Ang Thong sits roughly between Koh Samui and Koh Phangan geographically. Some operators offer Ang Thong tours departing from Koh Phangan as well. If you are planning a Koh Phangan day trip alongside Ang Thong, factor in the logistics — they are separate days.
For a suggested schedule that fits Ang Thong into a longer stay, see the 4-day Koh Samui itinerary. For accommodation close to the north coast departure piers, browse /hotels/ and filter by Maenam or Bophut.
