Viet Hai is a small farming and fishing village on the eastern side of Cat Ba Island, isolated for most of its history because the only access was on foot through the national park or by boat. A road of sorts now reaches the village, but the place is still remarkably quiet — about 300 inhabitants, a handful of homestays, water buffalo grazing along the lanes.
The classic way to visit is to hike across the national park from the headquarters, arriving at Viet Hai for lunch, and then take a boat back to Cat Ba Town through Lan Ha Bay — a full day, but a memorable one combining the island's two best experiences. Boat-only visits as part of a kayaking day are easier and almost as rewarding; ask any Cat Ba agency.