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.
Unlike its famous twin, Lan Ha Bay reserves a more pristine scenery with an intense concentration of limestone mountains in which the sea surface has partitioned into smaller bays and gulfs. Many lagoons, bays, and caves still remain untouched.
The bay has up to 139 golden sandy beaches, small but pretty and isolated as “blue straits” inviting tourists to explore. Many sandy beaches stretching between two rocky mountains, quiet with no big waves, are really the ideal beaches.
Lan Ha is a peaceful sea with small fishing villages existing isolated from the rest of the world. There are wooden floats raising different species such as the green mussel, geoduck, cobia, crab, abalone, grouper, which can serve visitors according to their needs. By small boat, visitors can glide through the ravine, lagoons to visit the caves, resting on the beach.
Unlike Halong, the Lan Ha Bay itinerary is quite flexible, which means you can do any water activities that you can imagine, jumping down from the boat, going fishing with local, doing kayaking to anywhere you desire to explore, diving or surfing, or even rafting. Your passion for water is only limited by your own imagination.
According to lonelyplanet.com and perladawnsails.com