The main island is Cat Ba covering about 100km2 and 30 nautical miles from Hai Phong port.
Cat Ba archipelago is recognized as a World Biosphere Reserve by UNESCO. Cat Ba National Park covers 15,200ha including 9,800ha forest and 5,400ha sea to create an ideal ecological environment.
Coming to Cat Ba, you can bathe in Cat Co Beach 1, Cat Co Beach 2, Da Bang Beach, Ben Beo Beach and Co Tien Beach and more. Also, you can visit Trung Trang cave, Hoa Cuong cave or join in ecological tours in Cat Ba National Park and in Phu Long commune.