This is a list of islands whose land is divided by one or more international borders.

Sea islands

Lake islands

River islands

Historically divided islands

Other islands have been divided by international borders in the past but they are now unified. The definite borders of modern nation states do not apply in other forms of societal organisation, where "divided" islands may consequently be less noteworthy. For example, in Ancient Greece, the island of Euboea was divided among several city-states, including Chalcis and Eretria; and before its settlement by Europeans, the Island of Tasmania was divided among nine indigenous tribes. Islands in wartime may be divided between an invading and defending power, as with Crete in 1645–1669 between the Ottoman Empire and the Republic of Venice. Examples of formerly divided islands include: A few former islands have disappeared because of changes in water levels:

Subnationally divided islands

There are islands that lie across different provinces or states of the same country. Killiniq Island of Canada, which is divided between Newfoundland and Labrador and Nunavut, whereas Melville Island and Victoria Island are divided between Nunavut and the Northwest Territories. In Australia, the Boundary Islet is divided between Tasmania and Victoria. Smith Island in Chesapeake Bay and Assateague Island, a barrier island on the Atlantic coast of the United States, are divided between the states of Maryland and Virginia. Ellis Island contains a true exclave of the state of New York, which is largely the area of the original natural island, while all land reclamation extensions from 1890-1935 are in New Jersey. The states also share Shooters Island in Newark Bay. Owing only to accretion of silt, an island has arisen spontaneously in the Mississippi River at the location of the boundary trijunction of Arkansas, Louisiana, and Mississippi, and is thus divided among the three states. Pag, in Croatia, is divided between Zadar County and Lika-Senj County. Ishima, in Japan, is divided between Kagawa Prefecture in the South and Okayama Prefecture in the north. Chek Lap Kok in Hong Kong is divided between Islands and Tuen Mun districts, and Lantau is divided between Islands and Tsuen Wan districts. Chongming Island, while most commonly known as main part of Chongming District of Shanghai, is having a long and narrow part on the northwest of the island which administrated by Nantong, Jiangsu.