Beihai (bāˈhĪˈ) [key] or Pakhoi bäkˈhoiˈ, town (1994 est. pop. 135,500), Guangxi Zhuang Autonomous Region, SE China, an important fishing and trade port on the Gulf of Tonkin. Opened to foreign investment and trade in 1984, the city has large shipbuilding, food-processing, and marine product manufacturing facilities, and has acquired a reputation for harboring modern pirates. The chief pearl grounds of China are in nearby waters. The name sometimes appears as Pei-hai.