Lying south and east of Cat Ba Town, the 300 or so karst islands and limestone outcrops of Lan Ha are just as beautiful as those of Halong Bay and have the additional attraction of numerous white-sand beaches.
Due to being a fair way from Halong City, not so many tourist boats venture here, meaning Lan Ha Bay has a more isolated appeal. Sailing and kayak trips here are best organised in Cat Ba Town.
Geologically, Lan Ha is an extension of Halong Bay but sits in a different province of Vietnam. Around 200 species of fish, 500 species of mollusc, 400 species of arthropod, and numerous hard and soft coral live in the waters here, while larger marine animals in the area include seals and three species of dolphin.