Cygnet Island is a small islet, with an area of <0.5 ha, in south-eastern Australia. It is part of the Waterhouse Island Group, lying close to the north-eastern coast of Tasmania.
Recorded breeding seabird and wader species are Pacific gull, sooty oystercatcher and black-faced cormorant.
Other islands in the Waterhouse Group with breeding seabirds include:
Coordinates: 40°43′S 148°04′E / 40.717°S 148.067°E / -40.717; 148.067