Located to the south of Halong Bay, south and east of Cat Ba Town, Lan Ha bay spreads over an area of more than 7,000 ha, of which 5,400 ha are under the management of Cat Ba National Park. Lan Ha bay has 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, While the administrative boundaries place Lan Ha Bay within Hai Phong Province (not Quang Ninh Province, to which Halong Bay belongs). 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. The similarity in its formations, with some 400 islets scattered over the area, means that locals and tourists alike mutually acknowledge it as a part of the vast Halong Bay zone.
Unlike its famous neighbour, Lan Ha Bay reserves a more pristine scenery with an intense concentration of limestone mountains which the sea surface has partitioned into smaller bays and gulfs. With over a hundred beautiful, small beaches lying at the feet of the mountains, there is no problem finding a good spot for swimming, or organizing a private beach BBQ or overnight camp. Just imagine, after a long day of exploration in caves and grottos, you can totally relax while bathing in the azure waters and breathing the salty sea breeze of Lan Ha Bay.0