Cat Ba is the largest island in the Bay and approximately half of its area is covered by a National Park. The island has a wide variety of natural ecosystems, both marine and terrestrial, leading to incredibly high rates of biodiversity. Many types of natural habitats found on Cat Ba Archipelago include limestone karsts, tropical limestone forests, coral reefs, mangrove and sea grass beds, lagoons, beaches, caves, and willow swamp forests. Cat Ba Island is one of the only populated islands in Ha Long Bay, with roughly 13,000 inhabitants living in six different communes, and 4,000 more inhabitants living on floating fishing villages off the coast. The large majority of the population can be found in Cat Ba town, which is located at the southern tip of the Island (15 km south of the national park) and is the commercial center on the Island. Since 1997, Cat Ba town has grown rapidly and has become a tourist hub for both the Island and greater Ha Long Bay. Especially, almost all surface of this island is deployed free wifi access points as well as 3.75 generation mobile networks, which can make visitors can easily work when traveling.

Today, Increases in infrastructure on the Island including the building of bigger roads, dams to build harbors and to protect Cat Ba town from flooding, consistent electricity being brought to the island instead of having to rely on a generator, and large ferries and barges, able to transport trucks and cars to the Island from the mainland making daily trips to Cat Ba made it easier for tourists to visit the Island, leading to a rapid increase in tourism and development in Cat Ba town starting in 2001. Since then, a stop on Cat Ba Island has been included in the itinerary of many Ha Long Bay cruises and a strip of tall, thin, five story budget hotels line the seafront, receiving more than 350,000 visitors a year. Currently, over 105 hotels are listed in Cat Ba Island’s tourist directory pamphlet, from cheap budget hotels to flashier upscale resorts, and construction is underway on many more. Right now, construction is under way on the colossal Cat Ba Amatina, an enormous project that will transform the southern coast of the island. The Amatina compound will be "a world-class integrated marina, casino, resort and theme park" spanning 171.57 hectacres and  will be able to host almost 6,000 residents at a time. The Amatina will boast "seven resorts with over 800 villas, three marinas, one international convention palace, 6 five star hotels and 1 four star hotel" . The scale of this project is gigantic and will basically create a luxurious mini-city on Cat Ba and will attract tourists from around the world. Cat Ba Island has become the adventure-tourism capital of Vietnam, and many of the activities advertised are nature-based. Visitors can kayak and take boat cruises through Ha Long Bay and the Cat Ba Archipelago, hike through the national park, mountain bike around the Island, spend time on Monkey Island just offshore, explore the Island's many caves, swim on Cat Co 1, 2, or 3 or even rock climb on the limestone karsts. With its stunning scenery, its association with Ha Long Bay, its proximity to highly populous cities like Haiphong (50 km) and Hanoi (150 km), and even China and plenty to do, Cat Ba Island has become a major travel destination for foreign and Vietnamese visitors alike. {itpsharepoint}