Luon Cave is located on Bo Hon Island, 14 km south of Bai Chay. In front of the cave is Con Rua island, on the right is the Heavenly Gate. Here the cliff stands, four seasons of clear blue water like a mirror. At the water's edge, a bow-shaped gate opens at the foot of the island, which is Luon cave. Through the beautiful city gate, we meet a flat circular lake of four luxuriant trees and cliffs, on which every pack of monkeys runs and jumps. The ancient sapling trees are rattles, the sausages orchids spread in fragrant flowers and under the calm blue water is the vibrant life of marine species such as shrimp, fish, crab, squid and so on.

This is a closed island group, which reaches the sea only by a 4m wide, 3 m high and 100 m long. The brackish lake in the cave is surrounded by four mountains, about 1 km2 wide. On the cliffs, there are also fossilized freshwater shells, proving that people here once lived and that day it was a deep valley. These types of caves in Ha Long Bay are not many, but perhaps the most interesting and attractive things that attract tourists here are the natural scenery. It is a combination of harmony, harmony between the shape of the mountain, the color of the sky and clouds to each grass, it seems that there is no defect in the creation.

The cruise ships cannot enter the cave but only anchor near the door. Visitors who want to enter must go to the small boats, each carrying about 10 to 15 people. Both going in and out took about 20 minutes, so you should bring rescue buoys. Take a boat into the cave visitors do not have to pay because they are included in the entrance fee.