Jiuduansha is a collection of four intertidal wetland shoals at the mouth of China's Yangtze River. They are administered as an island region of the municipality of Shanghai's Pudong New Area.

The islands of Shanghai are those under the jurisdiction of the Shanghai municipal government. They comprise three large inhabited islands and a shifting number of smaller, uninhabited ones. Most are alluvial islands in the Yangtze River Delta in China, although a number of islands in Hangzhou Bay off Jinshan District are also administered by Shanghai. The alluvial islands are relatively young and their number varies over time. In 2006, the city's 19 uninhabited islands covered 226.27 square kilometers (87.36 sq mi), with a total coastline length of 309 kilometers (192 mi).