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Ang Thong Marine Park: Koh Samui Day Trip Guide

Last updated 2026-07-08

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TL;DR: Ang Thong National Marine Park is a 42-island archipelago of limestone karsts and hidden lagoons about 30km north-west of Koh Samui, and the standard way to see it is a full-day boat tour. Group boat tours run about ฿1,200-2,000 (~US$36-61) per person and small-group speedboat tours about ฿1,800-2,800 (~US$55-85), typically an 8-hour day from a 7-8am hotel pickup, including lunch, snorkelling gear, kayaking and transfer. On top of that you pay the national park entrance fee of ฿300 (~US$9) for foreign adults and ฿150 (~US$5) for children, usually collected separately. Highlights are the Emerald Lake (Thale Nai) on Koh Mae Ko, reached by a 240-step climb and closed to swimming, and the panoramic viewpoint on Koh Wua Talap. The park closes each year for monsoon season, roughly 1 November to mid-December. All prices ฿33 = US$1 (July 2026).

If you’ve searched “Ang Thong Marine Park,” you’ve seen the photo: a maze of jungle-topped limestone islands rising out of impossibly green water, with a hidden emerald lagoon at the centre. That’s Mu Ko Ang Thong, a 42-island national marine park north-west of Koh Samui, and the only realistic way to visit is a full-day boat tour. This guide breaks down tour prices and what’s included, the national park fee that catches people out, the two headline stops (the Emerald Lake and the Koh Wua Talap viewpoint), kayaking, and the seasonal closure that can scupper a trip if you don’t plan around it. Every figure below is checked against current 2026 operator listings and park data, cited at the end. Prices are in Thai baht with US dollars at ฿33 = US$1 (July 2026).

What is Ang Thong National Marine Park?

Ang Thong is a protected archipelago of 42 islands of limestone karst, hidden lagoons and white-sand beaches, spread across the Gulf waters roughly 30km north-west of Koh Samui. The name means “golden bowl,” and the park is uninhabited apart from park staff, which is why it’s kept its dramatic, undeveloped scenery. You can’t stay on Samui and just hop over on a public ferry; access is via organised day tours that leave from Koh Samui (and Koh Phangan) piers. The landscape, all sheer cliffs, sea caves and viewpoints, is the whole point, and it looks nothing like the developed beaches of Samui itself.

Ang Thong tour options and prices

A standard day is a big (slow) boat tour from about ฿1,200-2,000 or a faster speedboat tour from about ฿1,800-2,800, both running roughly 8 hours with lunch, gear, kayaking and transfer included. Here’s the shape of it:

OptionBoatDurationPrice (per person)Note
Group day tourBig / slow boat~8 hrs (7-8am pickup)฿1,200-2,000 (~US$36-61)Cheapest; steadier, slower ride
Small-group tourSpeedboat~8 hrs (7-8am pickup)฿1,800-2,800 (~US$55-85)More islands, faster, bumpier
Private charterSpeedboatFull day, flexible฿8,000-20,000 (~US$242-606) total for boatSet your own pace

National park fee (฿300 / ~US$9 adult, ฿150 / ~US$5 child) is additional on every option. Prices compiled from 2026 Ang Thong operator listings; see Sources. Prices at ฿33 = US$1 (July 2026).

Standard inclusions are hotel pickup and drop-off, lunch, snorkelling gear, drinking water and kayaking. Confirm exactly what your operator bundles before booking, since inclusions and the number of island stops vary between the slow boat and speedboat trips.

The national park entrance fee

Expect to pay ฿300 (~US$9) per foreign adult and ฿150 (~US$5) per child on top of the tour price, usually collected separately. This is a Thai Department of National Parks fee, not a tour-company charge, so no operator can waive it, and most quote their tour price without it. Some collect it at booking, others take cash on the day, so ask your operator directly whether the fee is included and carry small baht notes just in case. It’s the single most common “surprise” on the bill, so budget for it up front.

Emerald Lake (Thale Nai)

The Emerald Lake on Koh Mae Ko is the park’s signature sight, a hidden saltwater lagoon reached by a roughly 240-step climb, and swimming in it is not allowed. From the viewing platform at the top you look down on the vivid green water encircled by limestone cliffs, connected to the sea by an underground channel. It’s a look-and-photograph stop rather than a swim; the climb is short but steep, so wear shoes with grip rather than flip-flops. On a clear day it’s the most memorable image you’ll take home from the trip.

The Koh Wua Talap viewpoint

Koh Wua Talap, the park’s headquarters island, has the classic panoramic viewpoint, a steep climb of about 430 metres’ elevation to a 360-degree view over the whole archipelago. This is the shot you’ve seen of karst islands scattered across turquoise sea. It’s a genuine workout on an uneven, rope-assisted path, so it’s optional on most itineraries and not for everyone, but the payoff at the top is the best overview of the park you’ll get. Take water, and don’t attempt it in flip-flops. Koh Wua Talap is also where the park’s main beach and facilities sit.

Kayaking and snorkelling

Kayaking is included in most standard tours (not a paid add-on), typically a guided 30-45 minute paddle through the channels, sea caves and rock arches between the islands. It’s one of the highlights, letting you get close to the cliffs and into spots the big boats can’t reach. Snorkelling is also included, and while it’s decent, it’s not the park’s main draw; come for the landscape and the kayaking rather than expecting world-class reefs. Check whether your specific tour includes both, since the slow-boat and speedboat itineraries differ.

Best time to go, and the annual closure

Ang Thong is best from around late December to April, and it closes every year for the monsoon, roughly 1 November to mid-December. During that closure, strong winds and rough Gulf seas make the crossing dangerous and the park inaccessible; it reopens on a weather-dependent date usually between 10 and 20 December. Even outside the official closure, individual tours can be cancelled at short notice if the sea is too rough, so leave a spare day in your plans and check the forecast. This is the opposite of Thailand’s Andaman coast, where the wet season falls mid-year, so don’t assume Samui follows the same calendar. See the best time to visit Koh Samui for the full seasonal picture.

Honest downsides

  • The park shuts for over a month. If you’re travelling roughly 1 November to mid-December, you may not be able to go at all, so check before you build a trip around it.
  • It’s a long day with real transit. Expect around 8 hours door to door, a fair chunk of it on the boat, plus an early pickup.
  • The viewpoints are a proper climb. Both the Emerald Lake steps and the Koh Wua Talap viewpoint are steep; they’re optional, but the best views require the effort.
  • The park fee feels like a surprise. It isn’t a scam, it’s a regulatory charge, but if you only budgeted the advertised tour price, add ฿300 (~US$9) per adult.
  • Snorkelling is good, not great. Come for the karst scenery and kayaking; if reefs are your priority, other Gulf sites suit better.

Bottom line

Ang Thong is the standout day trip from Koh Samui for scenery: 42 karst islands, a hidden emerald lagoon and a viewpoint that puts the whole archipelago at your feet, all bookable as a single organised day. Pick a speedboat if you want maximum island time, budget separately for the ฿300 (~US$9) park fee, and travel in the dry season while the park is open, avoiding the roughly 1 November to mid-December closure. Pair it with the rest of your trip using outthailand.com’s things to do in Koh Samui and Koh Samui 3-day itinerary guides, and browse what’s on to slot the trip around anything else happening while you’re on the island.

Sources

Frequently Asked Questions

How much does an Ang Thong Marine Park day trip cost?

Budget about ฿1,200-2,000 (~US$36-61) per person for a standard group boat tour, or ฿1,800-2,800 (~US$55-85) for a smaller-group speedboat tour, both usually a full day of around 8 hours with lunch, snorkelling gear, kayaking and hotel transfer included. On top of that you pay the national park entrance fee of ฿300 (~US$9) for foreign adults and ฿150 (~US$5) for children, which is generally collected separately. Private charters are far pricier, often ฿8,000-20,000 (~US$242-606) for the boat depending on size.

Is the national park fee included in the Ang Thong tour price?

Usually not. Most operators quote the tour price without the ฿300 (~US$9) adult / ฿150 (~US$5) child national park entrance fee, which is collected separately, sometimes at booking and sometimes in cash on the day. Always confirm with your operator whether the fee is included so you're not caught out, and carry small baht notes just in case. The fee goes to the Thai Department of National Parks, not the tour company, so no operator can waive it.

What is there to see and do at Ang Thong?

The signature sights are the Emerald Lake (Thale Nai), an inland saltwater lagoon on Koh Mae Ko reached by a roughly 240-step climb, and the panoramic viewpoint on Koh Wua Talap, the park's headquarters island. A standard day mixes a viewpoint hike, kayaking through the channels and rock arches (about 30-45 minutes), snorkelling, swimming and beach time across the 42-island archipelago. The Emerald Lake is closed to swimming, so it's a look-and-photograph stop rather than a dip.

Can you swim in the Emerald Lake at Ang Thong?

No. The Emerald Lake (Thale Nai) on Koh Mae Ko is a protected inland saltwater lagoon, and swimming in it is not allowed. You reach it by climbing roughly 240 steps to a viewing platform, where you look down on the striking green water ringed by limestone cliffs. It's one of the most photographed spots in the park, but the experience is the view and the short climb, not a swim. Wear proper shoes for the steps, which can be steep and slippery.

When is the best time to visit Ang Thong Marine Park?

The park is best from around late December to April, in the drier, calmer Gulf season. It closes every year for the monsoon, roughly 1 November to mid-December, when strong winds and rough seas make the crossing dangerous, reopening on a weather-dependent date usually between 10 and 20 December. Even outside that official closure, individual tours can be cancelled at short notice if the sea is too rough, so build in a spare day and check the forecast. See outthailand.com's best-time-to-visit guide for the wider seasonal picture.

How do you get to Ang Thong from Koh Samui?

You go as part of an organised tour; there's no scheduled public ferry. Operators pick you up from your Koh Samui hotel between about 7am and 8am, drive you to a departure pier, and cross by big boat or speedboat to the park, which sits roughly 30km north-west of the island. The whole day runs about 8 hours door to door. Book through a reputable operator or booking platform, since a self-arranged trip isn't practical for a protected marine park like this.

Big boat or speedboat for Ang Thong?

A big (slow) boat is cheaper at about ฿1,200-2,000 (~US$36-61) and gives a steadier, more relaxed ride, but spends longer in transit and covers fewer stops. A speedboat costs more at about ฿1,800-2,800 (~US$55-85) but reaches the park faster, leaving more time at each island and often visiting more of them. If you get seasick easily or want a calmer pace, the big boat suits; if you want maximum island time and don't mind a bumpier, faster ride, pay up for the speedboat.

Is Ang Thong Marine Park worth it?

Yes, for the scenery: the 42-island karst landscape, the Emerald Lake and the Koh Wua Talap viewpoint are genuinely spectacular and unlike anything on Samui itself. It's a long day with a fair bit of boat time and some steep climbing, and the snorkelling is decent rather than world-class, so it rewards travellers who come for the landscape and the kayaking over those chasing the best reefs. Go on a calm-weather day in the dry season for the best of it.

Out Thailand Team

Based in Chiang Mai

The Out Thailand team lives in and around Chiang Mai and writes practical, on-the-ground guides to events, cost of living, and daily life in Thailand.