PLACE · HẠ LONG BAY
Luồn Cave.
On the northeastern side of Bồ Hòn Island, Luồn Cave opens onto a small lake beyond a low passage through limestone. Curved cliffs enclose the water, making a quiet pocket within the wider landscape of the bay.

HẠ LONG: FROM PASSAGE TO LAGOON
Through a threshold of stone
The Hạ Long Bay heritage authority describes Luồn Cave as a tunnel with a submerged floor, connecting the sea to a small lake farther inside. Steep cliffs surround the lake and give the place its distinctive shape.
The Vietnamese name “Luồn” evokes the act of passing through: a narrow entrance first, then water opening beyond it. The place unfolds in layers, the bay outside, the limestone threshold, and the lake held within the cliffs.
Place details are adapted from the Hạ Long Bay heritage authority.
Read the official place guideA CLOSER LOOK
What shapes Luồn Cave
- 01
A submerged passage
A natural tunnel running low beneath the limestone.
- 02
A small lake inside
The cave connects the water outside to a lake within.
- 03
Curved limestone walls
High cliffs surround the lake and frame an enclosed space.