The rugged and scenic Cat Ba Island is the largest island in Halong Bay. About half of it is a dedicated National Park, home to both marine life and mammals, including the endangered Cat Ba langur (also known as the golden-headed langur), civet cats and Oriental giant squirrels. In 2004, the park was recognized by UNESCO as a Biosphere reserve of the world. (Many tour operators offer trekking and canoeing options through the park.)
The eastern side of the island is home to several beaches worthy of exploration, fishing villages and a small town (population 8,000) that tends to get crowded on weekends and public holidays. Here, you’ll find a promenade, and a strip of hotels, bars and restaurants.