Tham Morakot — the Emerald Cave — is the headline act of every Trang islands trip. On the west side of Koh Muk, a dark opening at the foot of the cliffs leads into a water-filled passage of roughly 80 metres. You swim (or are towed in a line by the guides) through the gloom, and then the tunnel opens into a small, enclosed beach of white sand surrounded by sheer walls hung with jungle, with a circle of sky above.
The cave can only be entered around the right tide, when there is enough water to swim but enough headroom to pass. Boats plan their schedules around it, so it can be very busy in the late morning in high season, with life-jacketed swimmers queueing at the entrance. Arriving early — easiest from Kradan or Koh Muk on a private longtail — makes all the difference.
Local stories say the hidden beach was once a hiding place for pirates’ treasure. True or not, it is one of the most memorable swims in Thailand.
Top things to do at Emerald Cave (Tham Morakot), Koh Muk
Swim through to the hidden beach
Wear a life jacket, stay with your guide and keep your head up in the dark section. Waterproof torches help.
Go early
A private longtail from Kradan or Koh Muk can reach the cave before the big day-trip boats. See the private boat options.
Combine it with the 4-islands trip
Most tours pair the cave with Koh Kradan, Koh Ngai and the snorkelling stops at Koh Chueak and Koh Waen.
How to get to Emerald Cave (Tham Morakot), Koh Muk
- From Koh Kradan, the cave is a short longtail ride across the channel to the west coast of Koh Muk; resorts can arrange a boat.
- From Koh Lanta and Trang, it is included on nearly every 4-islands tour.
Insider tips
- Non-swimmers can do it with a life jacket and a guide, but it is dark and can feel claustrophobic.
- Bring water shoes — the cave floor and entrance can be rocky.
- Leave valuables on the boat or in a dry bag.
- National park fees may apply around the Trang islands; check with your operator whether they are included.
Best tours & tickets for Emerald Cave (Tham Morakot), Koh Muk
These experiences are the easiest way to see Emerald Cave (Tham Morakot), Koh Muk:
Island-hopping day trip from €24 Koh Lanta: 4 Islands, Emerald Cave & Koh Kradan by Longtail
The most-reviewed trip that reaches Koh Kradan, with well over a thousand reviews. A traditional longtail takes you south from Koh Lanta to the Trang islands: Emerald Cave, snorkelling stops and a beach lunch. There are two options — pick the one that names Koh Kradan if the island is why you are going.
- Swim through Emerald Cave to the hidden beach on Koh Muk
- Snorkel stops on the reefs of the Trang islands
- Beach lunch — choose the option that includes Koh Kradan
Island-hopping day trip from €42 Koh Lanta: 4 Islands, Emerald Cave & Koh Kradan by Speedboat
The same classic route as the longtail trips, but by speedboat, which cuts the crossing time from Lanta and leaves more time in the water. Rated 4.7, with lunch on Koh Kradan. Speedboats are less comfortable in a choppy sea, so it is best in the calm months.
- Faster crossings by speedboat — more time at the stops
- Emerald Cave, coral reef snorkelling and island beaches
- Buffet lunch on Koh Kradan
Island-hopping day trip from €40 Trang: Full-Day Big Boat Adventure to Kradan & Chueak Islands
The best-established GetYourGuide trip from the Trang side: a full day on a bigger boat to Emerald Cave, Koh Kradan and the reefs of Koh Chueak. A bigger boat is steadier in a swell, though less nimble at the stops. Rated 4.2 from a small number of reviews.
- Emerald Cave and its hidden beach
- Koh Kradan and snorkelling at Koh Chueak
- A larger, steadier boat than a longtail
Island-hopping day trip from €112 Trang: 4 Islands Full-Day Tour with Snorkeling & Lunch
Another full-day 4-islands tour starting from Trang, with the Emerald Cave, Koh Kradan and snorkelling at Koh Chueak and Koh Waen, plus lunch. New on GetYourGuide and not yet reviewed — compare it with the Trang big-boat trip before you decide.
- Emerald Cave’s hidden lagoon
- White sand on Koh Kradan
- Reef snorkelling at Koh Chueak and Koh Waen, with lunch
