Weizhou Island, accessible by ferry from Beihai in about an hour, is China's largest volcanic island in the South China Sea and among the most rewarding day trips or overnight stops in Guangxi. The island is ringed by coral reefs — among the healthiest in the country — and the diving and snorkelling are genuinely good by Chinese standards. The basalt coastline, formed by relatively recent volcanic eruptions, creates dramatic cliff formations and sea caves accessible by boat or by walking the coastal path.
The two nineteenth-century French Catholic churches in the island's interior are the strangest element: Gothic stone churches rising from basalt fields in a fishing village, surrounded by tropical vegetation and attended by a population that converted generations ago and has remained Catholic ever since. The combination of excellent marine environment, unusual geology, and this incongruous religious heritage makes Weizhou more interesting than any other island on Guangxi's coast. Accommodation is basic but sufficient; stay overnight to catch the island at its quietest.