The Ground frogs are a large group of terrestrial species with comparatively narrow digits which vary in size from the species of Uperoleia and Crinia of body length 30 mm to large robust species in the genera Limnodynastes and Mixophyes which reach a length of 80 mm or more. There are nine species of Ground Frog recorded from the Harbour region. The Brown-striped Marsh Frog, Limnodynastes peronii, Spotted Grass Frog, Limnodynastes tasmaniensis, and Common Eastern Froglet Crinia signifera, still occur in suitable areas around the Harbour. The Brown-striped Marsh Frog in particular has adapted to a wide range of urban environments.

The remaining species of Ground Frogs no longer commonly occur around the Harbour and the last Museum records for several species from the southern shores are from the early part of the twentieth century. Two of the species of Ground Frog that were probably widespread in sandstone habitat around the Harbour are the Giant Burrowing Frog Heleioporus australiacus, and Red-crowned Toadlet, Pseudophryne australis. Both species are now listed 'Vulnerable' in New South Wales under the current state legislation.