The waters, from the mouth of the Haidian River, to the Qiongzhou Strait are deep enough for large ship traffic. Much of the rest of the bay, within a few kilometres of the shore, are very shallow, and at low tide, reveal land. Fishermen can be seen at this time walking out into the bay to collect shellfish.
Part of the western edge of Haidian Island is being extended in a major land reclamation project. Also, several new areas of land off the coast of Haikou are being created, including the Nanhai Pearl Artificial Island.