Sandy Island, New Caledonia
Sandy Island (sometimes labelled in French Île de Sable, and in Spanish Isla Arenosa) is a phantom island that was charted for over a century as being located near the French territory of New Caledonia between the Chesterfield Islands and Nereus Reef in the eastern Coral Sea. The island was included on many maps and nautical charts from as early as the late 19th century.
Source: Wikipedia — Sandy Island, New Caledonia (CC BY-SA 4.0)