This paper will examine the history of underwater fossil research in the Mt Gambier region, Australia, focusing on ongoing efforts to study, conserve, and protect underwater resources found in the freshwater sinkholes and limestone caves of the region; as such, the topic of this abstract fits best within the session The Archaeology of Submerged Landscapes and Inland Waters because it is concerned with cave sites that have become flooded. I will describe the considerable past efforts that were undertaken to extract fossils from Green Waterhole, as well as recently successful efforts to have this site registered as a South Australian Heritage Listed site, ensuring legislated protection for the cave and its deposits into the future. In addition, a new research program funded by the Australian Research Council and in collaboration with the Cave Divers Association of Australia and the South Australian Museum will be presented. The new work includes efforts to successfully recover fossils with as much contextual information as possible, especially geochronological and environmental data. Using these data, we expect to determine the geological age of the extinct megafauna recovered from the sites and the environments they inhabited; data critical for determining the degree to which humans or environmental change contributed to their demise. We will also evaluate the impact of such research on the preservation of the caves, ongoing efforts to conserve the geoheritage potential of the sites, and means of educating the public on the unique underwater resources they represent.