Cat Ba is the largest island in the Halong bay vicinity. Lan Ha bay, off the east side of the island, is especially scenic and offers numerous beaches to explore. While the vast majority of Halong bay’s islands are uninhabited vertical rocks, Cat Ba has a few tiny fishing villages and a fast-growing town. About half of Cat Ba island ( which has a total area of 354 sq km) and 90 sp km of the adjacent waters were declared a national park in 1986 to protect the island’s diverse ecosystems. These include sub-tropical evergreen forests on the hills, freshwater swamp forests at the base of the hills, coastal mangrove forests, small freshwater lakes and coral reefs. Most of the coastline consists of rocky cliffs, but there are a few sandy beaches tucked into small coves. The main beaches are Cai Vieng, Hong Xoai Be and Hong Xoai Lon.

There are numerous lakes, waterfalls and grottoes in the spectacular limestone hills, the highest of which rises 331m about the sea level. The growth of the vegetation is stunted near the summits because of high wind. The largest body of water on the island is Ech Lake, which covers an area of 3 hectares. Almost all of the surface streams are seasonal, most of the island’s rainwater flows into caves and follows underground streams to the sea, creating a shortage of fresh water during the dry season. The waters off Cat Ba island are home to 200 species of fish, 500 species of molluscs and 400 species of arthropods. Larger marine aninals in the sea include seals and 3 species of dolphins.

Stone tools and bones left by humans who lived here between 6000 and 7000 years ago have been found at 17 sites on the island. The most thoroughly  studied site is Cai Beo cave, discovered by a French archaeologist in 1938, which is 1.5 km from Cat Ba town. Trung Trang cave is easily accessible, however you will need a torch if you want to see anything. The cave is just of the park entrance along the main drag. The best weather on Cat Ba island is from late September to November, particularly the latter, when the air and water temperature is mild and skies are mostly clear. December to February is cooler, but still pleasant. From February to April rain is common. The summer months from June through August are hot and wet.

Cat Ba National Park

is home to 32 types of mammals-including Francois monkeys, will boar, deer, squirrels and hedgehogs and over 70 species of birds have been sighted, including of hawks, hornbills and cuckoos. Cat Ba lies on a major migration route for waterfowl such as ducks, geese and shore birds) who feed and roost in the mangrove forest and on the beaches. The 745 species of plants recorded on Cat Ba include 118 timber species and 160 plants with medicinal value. There are 45 park rangers stationed here to protect the flora and fauna. The most interesting part of the activities is a walk through a cave, then onto a mountain peak.  There is a very challenging  18km hike through the park that many enjoy. You need a guide, transport to the trailhead and a boat to return. All of this can be easily arranged in Cat Ba. The hike includes a visit to Viet Hai, a remote minority village. If you are planning on doing this hike, equip yourself with proper hiking shoes, a raincoat and a generous supply of water plus some food. 2 caves in the park are open to visitors. One has been preserved in its natural state while the other has historical significance – it served as a secret, bomb-proof hospital during American War. The park is home to an unique species of tree called Kim Giao. In ancient days kings and nobles would eat only chopsticks made from this timber, anything poisonous it touches turns the light colored wood to black.

Beaches 

The white sand Cat Co beaches make a great place to lounge around for the day. They are about 1 km from Cat Ba town and can be reached on foot or by motorbike. The 2 beaches are separated by a small hillock that can be climbed over in about 20 minutes. Most, however, take the easier route along a new, 700m, wooden seaside walkaway. Cat Co 2 is the less busy and more attractive of the two, and also offers simple accommodation and camping.