The Bay covers an area of 1,500 square kilometers filled with thousands of islets of all shapes and sizes, many named after their natural shapes such as Voi (Elephant), Ga Choi (Fighting Cock) and Mai Nha (Roof). The Bay is also well known for its fauna, on the islets and in the water. Its caves are great in number and remain to be discovered.

Quang Ninh province features a meandering coastline, numerous estuaries and tidal flats and more than 2,000 large and small islands. Exactly 1,030 of these have been named. Quang Ninh is a mountainous and coastal province with more than 80% of its area being made up of mountains and hills. The 2,000 some islands are also considered mountains.