Blue Lagoon Cat Ba

An 18-room guesthouse on Hà Sen street in Cat Ba town, Blue Lagoon sits at the quieter northern end of the island's main drag, within ten minutes' walk of the ferry pier and the Cat Ba National Park trailhead.

The 9.6 rating across 559 reviews points to consistent service rather than facilities — rooms are compact but maintained, and staff regularly arrange boat trips into Lan Ha Bay, the less-trafficked southern extension of Ha Long Bay that Cat Ba-based operators access more easily than mainland tours.

Cat Ba town itself is a working fishing port rather than a resort strip, which keeps prices grounded and morning markets lively. The island's karst interior makes for half-day hiking without needing a guide.