Located adjacent to Halong Bay, Lan Ha Bay is a peaceful bay in Cat Ba Islands system. Lan Ha Bay has about 400 large and small islands covered with green trees and vegetation. Limestone also makes up a large portion for the small islets in the bay. Nature is peaceful on the island. There are many calm water area suitable for swimming and kayaking around Sen Islet, Cu islet, Monkey islet. Stalactite caves such as Ham Rong, Do Cung or beaches at Tung Bear Cave, Cat Dua beach are some of other natural attraction in the area.

Lan Ha Bay has 139 beautiful and clean beaches with white sand. Gentle waves and calm sea make this a perfect place for swimming. Underneath the blue water, colorful coral reefs area such as Van Boi, Van Ha is worth a diving adventure. If you intend to learn about the bay, you will have to take a few days, but if you are short on time, you can ask boat owners to suggest a few destinations.

Cat Dua Island is the first stop on the tourist route in Lan Ha Bay. Most of the boats are not stopping here because fatigue but they come to admire what nature has bestowed on Cat Ba. The island is also called Monkey Island due to the existence of monkeys. They may storm out ready for snatching food from careless tourists. They can bite if someone provokes.