Koh Hong
Ko Hong, Ao Phang Nga
A limestone island with a lagoon hidden inside it, reachable only by tender or kayak through a low tunnel at the right state of tide.

Hong means room, and the name is literal. The island is a ring of limestone around a flooded interior lagoon, open to the sea only through a tunnel a few metres high. At low water you paddle in under the rock and come out inside a walled green room with no beach, no buildings and, for about twenty minutes at a time, no other boats.
The anchorage on the south side is one of the most forgiving in the whole bay: sand and mud, good holding, sheltered from the northeast monsoon that blows through the charter season. It is where a first-night anchorage usually goes on a Phang Nga itinerary, because a crew can set the hook once and leave it.
Note that there are two Koh Hongs in the Andaman Sea. This is the one inside Ao Phang Nga National Park, roughly fourteen miles from Ao Po. The other lies off Krabi in a different park with a different fee.
Where it sits
- Marina
- Anchorage
- On this itinerary
- Positions are projected from real coordinates. Coastlines are simplified and not for navigation.
Source: Ao Phang Nga National Park, cruising guides for the Andaman Sea. Checked 6 September 2026. Anchorage notes are planning information from cruising guides and operator itineraries, not navigational advice.