One of the outlying islands of the Ha Long Bay region and technically in Bai Tu Long bay, Quan Lạn has been sparsely inhabited for quite some time. There are a few thousand residents and an influx of local tourists from Hanoi on weekends and holidays. The island itself is pretty sandy and has a little forest, unlike others nearby such as Ban Sen. Today, ports exist both at the northern and southern tips of the island. It is a less developed and less touristy alternative to the more popular Cat Ba Island.

Quan Lạn Island belongs to Bái Tử Long Bay; part of an island range on the outside of the gulf of Bắc Bộ. It has an area of 11 sq. km, and features eight populated hamlets. Quan Lạn Island stretch toward East – West from the foot of Vân Đồn Range to the Gót Mount with many high mountains to the east barring waves and winds, protect the villages. The island is situated on an important navigation route that connects China, Japan, Thailand and Philippines to Vietnam. Along two sides of the island are tens kilometres of sand beaches. The sand is used for glass making. Since the 11th century, Quan Lạn had been one of the centres of the ancient commercial port of Vân Ðồn, which was animated and prosperous at the time. Today, there are still many vestiges linked to the ancient commercial port. This also explains why the island, lying deep in the sea, still has large pagodas and archaeological sites. On the island there is the Quan Lạn Communal House built in the 18th century. It is exceedingly beautiful and almost entirely preserved. Next to it, there is Quan Lạn Pagoda (Linh Quang Tự), which is dedicated to Buddha and God Liêu Hạnh. The pagoda also worships the statue of old Hậu, a local person who made lots of contributions to the construction of the pagoda. The statue features a gentle and cheerful old woman, which adds an original character to the pagoda. Beside Quan Lạn Pagoda lies Nghè Quan Lạn (Ðức Ông) Shrine, which is dedicated to Phạm Công Chính, a local hero who participated in the historical Vân Ðồn battle against the Yuan invaders. He was later honored as a god. Quan Lạn has many valuable sea products such as octopuses, butterfish, mackerel, holothurian, shrimp, and sái sùng.