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Emerald Cave ( Tham Morakot) from above
Emerald Cave ( Tham Morakot) with the hidden lagoon from the sky


The Emerald Cave regularly attracts tourists to Koh Mook (Koh Muk). This because the hidden lagoon on the west coast is the main attraction of this small authentic island. Not for nothing, of course! However, to see the lagoon you have to make a small sacrifice, namely swimming almost 80 meters through a dark cave! For some sure no problem and for others a big NO! After swimming the 80 meters you enter the beautiful hidden lagoon, a true mini paradise!

Man jumps into the water in front of the Emerald Cave

What’s in the Emerald Cave?

As soon as you see the light at the end of the tunnel you understand that this swim through the dark cave was worth it! The beauty is almost impossible to express in words and by the way difficult to capture on pictures! You are completely surrounded by high overgrown rock walls! There are even trees and shrubs with a stretch of beach which makes you feel like you are in a mini jungle. There really is only one entrance and exit and that is the cave you came through.

The shallow water in the lagoon is crystal clear and has a beautiful blue/green color, it’s because of the incoming sun, this reflects via the walls of the lagoon. Hence the name Emerald Cave.

woman swimming in the cave with the Emerald Cave in the background

Pirates and treasures!

Before the tourists discovered the Emerald Cave, the lagoon was mainly visited for a type of bird nest, these bird nests were (and are) used for bird nest soup. These nests make the birds out of their saliva. Many Chinese people assume that bird nest soup has a healing effect because of its proteins and vitamins. These nests are often stuck high up against the rock wall and were brought down with breakneck speed because they make good money.

Later the Emerald Cave (Tham Morakot) was also discovered by other people, pirates!  They used the lagoon as a storage place for their loot. So who knows, there might be a hidden treasure somewhere in the Emerald Cave!

Inside the hidden lagoon of the Emerald Cave
The Emerald Cave of Koh Mook

The best time to visit the Emerald Cave

If you want to see the Emerald Cave at its best you go to the cave between 10 AM and 2 PM. What’s that for? Then you have the most chance that the sun shines in the lagoon and the water gets the beautiful green color. Not entirely coincidental these are also the times when the lagoon is most visited. Do not visit the lagoon when the water is at its lowest, there is no water in the Emerald Cave. And what is the cave without Emerald? If you prefer paradise for yourself, go before 9 AM or at the end of the day after four o’clock.

Because the Emerald Cave belongs to a National Park it’s only open between November and April (high season). In the other months the hidden lagoon is closed so nature can recover. An additional reason that you are not allowed to enter the cave is that the sea can be rough in the rainy (low) season (May – October).

Couple in the Emerald Cave

Avoiding the crowds

Of course, such a beautiful natural wonder will never remain a secret for long and you will have to share it with many fellow travellers. Sometimes big flocks of people enter the cave at the same time, which makes the feeling of paradise a bit less. But if you can look through it a bit, it remains a nice tour to do! If you want the Emerald Cave as much as possible for yourself there are two alternatives to avoid the worst crowds:

Renting your own longtail boat

You can stay on the island of Koh Mook and make a day trip to the cave. For this you can rent a longtail boat yourself or together with some others. The boat driver will take you to the Emerald Cave and from there you can do it yourself!

In the cave is a rope that you can follow, so you don’t have to be afraid to get lost. The swim takes about 5 minutes, after the first turn it is pitch black in the cave. Ask for headlights if you are going to rent the longtail boat, that would be a good idea! After the short swim (which feels longer) you enter the beautiful lagoon! You did it!

Do you prefer that boat driver comes along in the cave and the Emerald Cave, please discuss this in advance!

Also from the beautiful Koh Kradan, an island southwest of Koh Mook, you can easily rent a longtail boat to visit the Emerald Cave.

Crab on Farang Beach / Charly Beach, blue sea with fish and longtail boat the beach of Koh Mook

Rent a kayak

Yes, you can visit the Emerald Cave all by yourself! On Charlie Beach, a beach in the south of Koh Mook, you can rent kayaks for a reasonable amount of money. A head lamp and life jacket are included in the rental price. It takes about half an hour to paddle to the cave. Always ask the locals what is the best time to go before you plan the trip. If you really don’t want to swim you can plan the tour when the water is not too high and you can take the kayak through the cave. If you have to or want to swim you can tie the kayak to a rope outside the cave.

Kajaks on Charlie's Beach
Kayak and people in the cave of the Emerald cave

Organized tour to the Emerald Cave

Can you deal with some fellow travelers? Then the easiest and most chosen way is to book an organized tour to the Emerald Cave on Koh Mook but also from the various surrounding islands. Koh Lanta is a popular departure point as well. The Emerald Cave is then part of a snorkel tour. Usually you will also visit some other beautiful places like Koh Ngai and Koh Kradan and food, drinks and snorkel rent is included in the price.

For a tour of about 7 hours you pay about 1.400 baht. Ask the local travel agency about the possibilities. You can also book a tour from Koh Mook itself.

A school of fish in the sea

Everything you need to know about Koh Mook

In the InfoBox you’ll find even more information about the lovely authentic island of Koh Mook and its special sights!

Sleeping on Koh Mook

This is our selection of the best sleeping places on Koh Mook:

Read also our review of MookLamai Resort or the full article about the best hotels on Koh Mook.

Good eats and drinks on Koh Mook

If you want to know more about the above restaurants read our article the best restaurants on Koh Mook!

Going out on Koh Mook

Koh Mook does not (yet) have a real nightlife but there are some nice bars. The Koh Mook Ting Tong Bar is a cozy place where you can have a drink while enjoying a fire show. The Perfect Bar and Restaurant has happy hour from 16:00 to 18:00 and is a nice place by the sea to start the evening.

The transport on Koh Mook is simple and well arranged! On the island scooters ride with a sidecar, there you can ride with several people at the same time. Each ride on the island costs 50 baht p.p. one way, so negotiating the price is not necessary!

See & do on Koh Mook

Check out our selection of some impressive pictures in Picture This #13 Koh Mook

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