Cat Ba Town is the only settlement of any size on the island, a curved strip of buildings facing a working harbour on the south coast. Most of the new construction is tourist-oriented — concrete hotels along the seafront, a strip of restaurants and tour agencies, the usual karaoke bars — but step a block back from the water and you find a real Vietnamese fishing town with a morning market, a wholesale fish dock, and a couple of small temples.
The seafront promenade is the social heart of the town, particularly in the evening when locals come down to walk and the cafés put out plastic chairs. Boats for Lan Ha Bay leave from Beo Wharf at the eastern end of the harbour; the ferry to Hai Phong departs from the main pier in the middle. Easy to walk end to end in 20 minutes.