Fraser Island is the world's largest sand island, composed of sand accumulated over approximately 750,000 years.
It hosts an outstanding level of marine biodiversity and is considered likely to be the richest area in the world in terms of animal diversity.
It is heavily forested and hosts high levels of endemism.
The southern portion of the atoll surrounds its former lagoon, Te Nggano, which is now the largest lake in the Pacific Ocean.
Riversleigh and Naracoorte were inscribed for their extensive fossil records, and are listed among the ten richest deposits in the world.
Both are illustrative of separate, key stages in the evolution of mammals on the Australian continent.