The Sidmouth Rock is a rock islet or small island, located in the Southern Ocean, off the southern coast of Tasmania, Australia. The island is situated approximately 28 km south-east of South East Cape and is contained within the Southwest National Park, part of the Tasmanian Wilderness World Heritage Site. An erosional remnant of the Tasmanian mainland with a diameter of 90 m, the island is estimated to have separated from the Tasmanian mainland at least 15,000 years ago.

Location and features

The Sidmouth Rock is located approximately 2 km east of Eddystone, another islet located off the South East Cape. The islet is frequently wave-washed and supports no land-dwelling life.

Important Bird Area

Together with the nearby Eddystone and Pedra Branca islets, Sidmouth Rock constitutes the 2 ha Pedra Branca Important Bird Area, identified as such by BirdLife International because it supports over 1% of the world populations of shy albatrosses and Australasian gannets.