Qiongzhou Strait

The Qiongzhou Strait separates Hainan from the Leizhou Peninsula, linking the waters of the northern South China Sea with the Gulf of Tonkin. Its relatively narrow crossing made it a natural route between the island and the mainland, but currents, winds, and seasonal storms could make passage difficult. Boats carried officials, merchants, migrants, and agricultural goods, while fishing communities used the surrounding coastal waters. Reliable knowledge of departure points and local conditions mattered greatly to safe travel.

In the Ming period, an official ferry operated from Haikou on Hainan toward Xuwen on the mainland. A courier office established at Haikou in 1376 sent government documents across the strait to a relay station in Xuwen. The crossing also served merchants and travelers, linking the island's communities with the mainland even as winds, tides, and shallow harbor waters shaped maritime travel.