Flat Island

Flat Island may refer to:


 * Flat Island (Antarctica), in Robertson Bay
 * Flat Island (Hong Kong)
 * Flat Island (Spratly) in the South China Sea
 * Flat Island (Falkland Islands) in the south Atlantic Ocean
 * Flat Island Wildlife Sanctuary, in the Andaman Islands
 * Flat Island, a former separate island now merged by recent volcanic activity with McDonald Island, in the southern Indian Ocean
 * Flat Island, one of the Engineer Islands in southeast Papua New Guinea
 * Île Plate, also known as Flat Island, a small island off the north coast of Mauritius
 * Sandy Point, Newfoundland and Labrador