Situated in the east of Cat Ba Island, overlooking the Van Gate, adjacent to Halong Bay, Lan Ha Bay is a beautiful pristine arched bay with about 400 small and large islands. Unlike Halong Bay, all the islands in Lan Ha Bay are covered with trees or vegetation, even if it is a very small island. Lan Ha Bay has hundreds of limestone mountains with different shapes such as Guoc island (like a clog), Doi island (like a bat) and stalactite caves: Ham Rong cave, Do Cung cave, Ca cave, etc.

Different from Halong Bay, Lan Ha Bay has 139 beautiful, small and deserted sandy beaches as the "blue straits" inviting tourists to discover. Many quiet sandy beaches stretching between two rocky mountains with no big waves are really the ideal beaches. In the blue sea water is the colorful coral reefs such as Van Boi beach, Van Ha beach. The calm sea areas such as Sen island, Cu island, Monkey Island are beautiful locations where visitors can dive to admire the coral. Lan Ha Bay has also Cai Beo floating village, where more than two hundred households live on the houses designed on buoys. Today, domestic and foreign archaeologists still have been learning about the history of its existence for thousands of years.