The Hidden Lagoon at Koh Hong
The lagoon sits in the centre of Koh Hong, enclosed by a ring of limestone cliff. The only way in is through a narrow gap in the rock, either swimming or kayaking, depending on the tide. Once you're through, you're in a completely enclosed bay, open only to the sky above.
The water inside is typically calmer than outside, the colour shifts between deep green and turquoise depending on the light, and the acoustic effect of the walls means you can hear your own echo. It's one of those places that photographs don't quite do justice to.
Tide Timing
Access through the gap requires mid-tide or lower. At high tide, the entry becomes too narrow to swim through safely. All our tours are timed around the tidal window, your guide will confirm on the day. See our Koh Hong tides guide for more detail.
Questions People Ask
Can you swim into the lagoon or do you need a kayak?
Both work, and both are offered on our tours. Swimming through the narrow gap takes about 30 seconds. Kayaking gives you more control and keeps you drier. Most guests end up doing one each way. Your guide will explain both options before you go in. Read more about
kayaking at Koh Hong.
What happens if the tide is wrong when we visit?
All our tours are timed around the tidal window, so this is very rarely an issue. On the rare occasion that conditions make entry unsafe, your guide will let you know on the day. If the lagoon is completely inaccessible for the whole day, we offer a free reschedule or full refund.
How long do you get inside the lagoon?
Usually 20 to 30 minutes. That's enough time to swim around, take photos, float and take in the atmosphere. Most guests say it goes by very fast.
Is it scary going through the gap in the rock?
The gap is narrow enough that you'll feel the walls on either side, but it only takes a few seconds to get through. A small number of guests feel claustrophobic and choose to watch from the water outside instead. That's completely fine. Your guide will stay with anyone who doesn't want to go through.
Can children go into the lagoon?
Yes. Children do this regularly and most love it. We recommend they be comfortable in water and able to swim a short distance unaided. Life jackets are available and your guide will stay close. For very young children who aren't confident swimmers, the kayak option is usually better than swimming through.
What does it actually look like inside?
Imagine being at the bottom of a well, but the walls are 80 metres of jagged limestone and the ceiling is open sky. The water is calm and shifts between deep green and teal depending on the light. The sound is different too, you can hear your own echo. It looks like somewhere that shouldn't exist.