If you're looking at tours around Koh Samui, there's one destination that appears time and time again: Ang Thong National Marine Park. Made up of 42 limestone islands scattered across the Gulf of Thailand, it's one of the most photographed places in the country, famous for emerald lagoons, towering cliffs, hidden beaches and crystal-clear water.
The park sits around 30 kilometres north-west of Koh Samui and is only accessible by boat, making it one of the island's most popular day trips. Whether you choose a speedboat, catamaran or traditional cruise boat, a visit to Ang Thong offers a completely different side of Thailand from the busy beaches around Chaweng or Lamai.
What is Ang Thong Marine Park?
Established as a protected national park in 1980, Ang Thong covers more than 100 square kilometres of land and sea. Although there are 42 islands, only a handful are regularly visited by tour operators, helping preserve much of the park's natural beauty.
Expect dramatic limestone cliffs rising out of turquoise water, hidden coves, dense jungle, secluded beaches and some excellent snorkelling. The scenery is spectacular enough that the park even inspired parts of Alex Garland's novel The Beach.
The Emerald Lake
One of the highlights is Talay Nai, often called the Emerald Lake. This natural saltwater lagoon sits hidden inside a limestone island and can only be viewed after climbing a short staircase through the jungle. Looking down into the vivid green water surrounded by sheer cliffs is one of the signature views of Ang Thong.
Viewpoints Worth the Climb
Many tours stop at Koh Wua Ta Lap, home to the park headquarters and one of the most rewarding viewpoints in southern Thailand. The climb is steep and can be challenging in the heat, but the panoramic views over dozens of limestone islands are worth every step.
If hiking isn't your thing, you can simply relax on the beach below while enjoying the scenery.
Snorkelling, Kayaking and Swimming
Most Ang Thong tours include at least one snorkelling stop where colourful tropical fish, coral reefs and clear water provide excellent conditions for beginners and experienced snorkellers alike. Depending on the tour you choose, kayaking is often included, allowing you to paddle beneath towering limestone cliffs and into quiet bays that larger boats can't reach.
Swimming, beach stops and relaxing on deck are all part of the experience, making the day suitable for couples, families and groups of friends.
Which Tour Should You Choose?
There are dozens of operators offering trips to Ang Thong from Koh Samui. Some focus on speedboats, allowing you to visit more locations during the day, while others use larger catamarans or traditional boats that offer a slower, more relaxed journey with plenty of space to unwind.
Premium tours often include smaller groups, better food, kayaking, snorkelling equipment and hotel transfers. Budget options can be excellent value too, particularly for first-time visitors who simply want to experience the park.
Rather than recommending one operator over another, we suggest comparing what's included, travel times and group sizes before booking.
When is the Best Time to Visit?
Ang Thong can be visited throughout much of the year, although sea conditions vary depending on the season. During calmer months, the water is often exceptionally clear, making snorkelling and kayaking even more enjoyable. Tours may occasionally be cancelled during periods of rough weather for safety reasons.
Is Ang Thong Worth Visiting?
Without question. It's one of the easiest ways to experience Thailand's famous limestone islands without travelling hundreds of kilometres from Koh Samui. The combination of scenic boat journeys, snorkelling, hidden lagoons, jungle viewpoints and untouched beaches makes it one of the island's best day trips.
If Ang Thong is already on your list, it's worth spending a few minutes comparing the different tours available. Group sizes, boat types, inclusions and overall experience can vary considerably.
Browse our latest Ang Thong tours here:
https://www.samuiunlocked.com/tours/?tourSearch=Ang+Thong#tour-results
