Emerald Lake

Ang Thong Marine National Park


With an ethereal minty tint, the Emerald Lake (also called the Blue Lagoon or Inner Sea) on Ko Mae Ko is a large lake in the middle of the island that spans an impressive 250m by 350m. You can look but you can’t touch: the lagoon is strictly off limits to the unclean human body. A dramatic viewpoint can be found at the top of a series of staircases nearby.


Lonely Planet's must-see attractions

Nearby Ang Thong Marine National Park attractions

1. Viewpoint

1.74 MILES

This viewpoint might just be the most stunning vista in all of Thailand. From the top, visitors will have sweeping views of the jagged islands nearby as…

2. Ang Thong Marine National Park

2.7 MILES

Known officially as Mu Ko Ang Thong Marine National Park, this series of jungle-covered islands – the inspiration for Alex Garland’s cult classic novel,…

3. Hat Bang Po

19.5 MILES

Stretching along several kilometres of the island's northern shore, this beach is a quiet length of sand and an excellent choice for escaping the crowds.

4. St Anna Catholic Church

20.13 MILES

This small green-tiled church north of Na Thon is an interesting Catholic outpost on the island. Visitors can simply push down the latch and let…

5. Hainan Temple

20.33 MILES

Fronted by a pair of golden Chinese lions and adorned with bright coiling dragons, this is probably the most colourful Chinese temple (and guildhall) on…

6. Hat Na Thon

20.34 MILES

When the tide is out, it's fun picking your way along the sand flats around Na Thon, especially south of the scrawnier beach near the pier. These really…

7. Wat Chaeng

20.43 MILES

Saffron-robed monks shuffle around quietly in this peaceful wát, where a huge seated golden Buddha in front of the wheel of dharma is amongst the standout…

8. Coconut Museum

21.14 MILES

This tiny museum is a nod to Ko Samui's history as one of Thailand's premiere coconut supplying islands. As well as the chance to become educated on Samui…