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 but feel more isolated and untouched, and have the additional attraction of numerous white-sand beaches. Sailing and kayak trips here are easily organised in Cat Ba Town.
Geologically, Lan Ha is an extension of Halong Bay but sits in a different province. Around 200 species of fish, 500 species of mollusc, 400 species of arthropod (prawns, crabs) and numerous hard and soft corals live in the waters here, while larger marine animals in the area include seals and three species of dolphin.
The bay's admission fee is normally incorporated into the cost of tours.