🔄 Updated 21 Jun 2026
Ang Thong sits about 25 km west of Koh Samui. It's a national marine park covering roughly 42 islands of all sizes within Koh Samui district, Surat Thani province. The two spots most people come for are Mae Koh Island, with its hidden Emerald Lake, and Wua Talap Island, where the park headquarters is. You can only reach all of this by boat from Samui — there's no bridge or road — so most trips are full-day, leaving in the morning and returning in the evening.
What is Ang Thong, and why do people go?
The classic image of Ang Thong is a cluster of oddly shaped limestone outcrops rising straight out of the sea, with steep cliffs, green forest, and white-sand beaches tucked between the islands. The thing that wows people most is the Emerald Lake on Mae Koh Island — an emerald-green saltwater lagoon hidden in the middle of a valley, connected to the open sea through a cave beneath the rock. That's why people climb up to the viewpoint to look down on the whole lake from above.
- Emerald Lake, Mae Koh Island — a saltwater lagoon roughly 200 m wide and 250 m long, emerald-green water ringed by limestone hills. A short climb to the viewpoint lets you look down on it.
- Wua Talap viewpoint — climb to the hilltop for a 360° view of the islands in every direction. It's the shot a lot of people come specifically to take.
- Beaches and clear water — there are beaches for a swim and snorkeling spots to see coral and schools of fish along the rocks.
- Kayaking — paddle through rock gaps and along the cliffs. It's a popular add-on that many tours offer.
Want more out of Koh Samui? Book tours & activities
Booking online ahead on Klook or GetYourGuide is usually cheaper than the gate and skips the queue. Pick only the experiences you actually want — prices and availability are shown live on each site.
Emerald Lake, Mae Koh Island — the reason people come
The Emerald Lake on Mae Koh is why a lot of people are willing to get up early and catch the boat. From the boat landing, you climb a steep path the park has built for a while before you reach the viewpoint that looks down on the full ring of green water. The trail is a mix of stairs and rock surfaces with handrails — not very long but fairly steep, so shoes with grip are safer than slippery flip-flops.
- You can't swim in the Emerald Lake — it's a conservation zone, so you can only take in the view from the designated viewpoint.
- The climb is steep — there are stairs and handrails, but they're slippery in the rain. Young kids and older travelers should take it slow and have someone to steady them.
- The water color depends on the sun — the emerald green is clearest when the sun is out; on overcast days it looks duller.
Before you climb to the viewpoint
Bring water and a hat — the climb is exposed and can get hot. Sneakers or closed-back shoes will feel steadier than flip-flops. When it's busy the stairs get narrow and you'll have to wait to pass people, so build in a little extra time.
How to choose your boat: big boat vs speedboat
Ang Thong trips from Samui come in two main types: the big boat (a large, comfortable tour boat) and the speedboat. They differ in speed, time on the islands, how smooth the ride is, and price. The prices below are the ranges we've actually seen from operators on the island, but they swing with the season and promotions, so double-check with the seller before you book.
Big Boat tour
A large boat that rocks less, good for people who get seasick easily and for families with kids or older travelers. The journey takes longer than a speedboat but you get the full-day tour-boat atmosphere, and lunch on board is usually included.
Speedboat tour
Faster, reaches the islands sooner, and gives you more time on the islands — good if you want to hit several spots in one day. But it rocks and slams into the waves harder, so anyone who gets seasick easily may not feel great.
Package with kayaking included
Many operators let you choose whether kayaking is included or not. If you're set on paddling, pick a package that already includes it — it works out cheaper than paying extra on the spot. Confirm exactly what's included before you book.
What to know about pricing
Ang Thong tour prices swing with the season and the size of your group — high season is pricier and more crowded. Some operators include the park entry fee, others don't. Ask clearly whether the price covers the park fee, food, snorkeling gear, and kayaking before you compare prices.
Park entry fee and extra costs
On top of the boat tour, there's a national park entry fee charged separately. Some tours include it; others have you pay on the spot at the island. The fee is cheaper for Thais than for foreign visitors. Carry some cash just in case you have to pay it yourself.
- Park fee, foreign visitors — around ฿300 for adults, around ฿150 for children.
- Park fee, Thai nationals — cheaper than for foreigners (bring your ID card to show).
- Check whether it's included — many packages already include the fee; if not, you pay it yourself at the island, so bring cash.
- Other costs — renting extra snorkeling gear, the kayak fee (if not included), and snacks or souvenirs on the boat.
When to go, and when the park is closed
Ang Thong isn't open all year. The park has an annual closure during monsoon season to let nature recover and for safety. Last year the announced closure ran roughly 1 November to 15 December — the seas are rough then and trips can't run. The calm, clear-sky stretch is usually the dry season, around February to April. Plan around it, and check that year's closure dates with the park or your operator before you book flights tied to this trip.
An honest note on weather and cancellations
Even outside the annual closure, a trip can be canceled if the seas are rough or the weather isn't safe that day. It's a safety call, not something to get annoyed about. Leave a spare day in your plan in case your booked date falls through, and ask the operator about their refund and rebooking policy clearly before you pay.
What an Ang Thong day looks like, hour by hour
Most trips are full-day, out in the morning and back in the evening. The order of stops may shuffle depending on the tides and your group, but overall it looks roughly like this — to give you a picture before you book.
Leaving Samui by boat
Mae Koh + Wua Talap
Kayak, snorkel, then head back
Getting ready and staying safe before you board
- Life jacket — wear it whenever you're on a small boat and while swimming or kayaking. Don't take it off because it's annoying; if the tour doesn't hand one out, ask for it.
- Seasickness — if you get it easily, take a tablet about half an hour before departure, choose the big boat that rocks less, and sit in the middle of the boat.
- Sun and sunburn — the sun at sea is strong, so put on sunscreen (reef-friendly is even better) and wear a light long-sleeve top when you're in the water for a while.
- Keeping things dry — put your phone and camera in a waterproof bag, wear closed-back shoes with grip, and pack a dry change of clothes for the way back.
- Trash — carry your trash back to shore to throw away. This is a conservation zone, so don't toss anything into the sea or leave it on the islands.
Getting to the pier on Koh Samui
If your tour doesn't include hotel pickup, you'll need to get to the pier yourself. If you rent a motorbike, watch out for Samui's roads — some stretches are steep and winding — and always wear a helmet. Leave extra time, because the boat departs on schedule and you can miss it if you're late.
Want a well-located base before the early boat trip?
See 10 great Samui hotels to book →