Rodondo Island is a granite island, ringed by steep cliffs up to 200 m high, with an area of 106 ha and a high point of 350 m.
It is part of Tasmania’s Rodondo Group, lying in northern Bass Strait only 10 km south of Wilsons Promontory in Victoria, and so being the northernmost point of Tasmanian territory.
It is a nature reserve with a breeding colony of over one million mutton birds or short-tailed shearwaters.
The island was sighted by Lieutenant James Grant on 9 December 1800 from the survey brig HMS Lady Nelson and named "from its resemblance to that rock, well known to all seamen in the West Indies", presumably Redonda, between the islands of Montserrat and Nevis.
The first landing was in January 1947 when a party led by John Béchervaise spent a week exploring the island and surveying its natural history.
Rodondo's vegetation communities include Disphyma herbfield, Stipa tussock grassland, Poa poiformis tussock grassland, Melaleuca armillaris low closed forest, Allocasuarina verticillata low open forest, clifftop shrubland, and Eucalyptus globulus open forest.
As well as the shearwaters, recorded breeding seabird and wader species include little penguin, fairy prion, Pacific gull and sooty oystercatcher. White-bellied sea-eagles have nested on the island. The island is part of the Wilsons Promontory Islands Important Bird Area, identified as such by BirdLife International because of its importance for breeding seabirds.Reptiles present include the metallic skink, White's skink and southern water skink, Rodondo being the only place the latter has been recorded on Tasmanian territory.