This report is part of a series of eco-narrative documents that synthesize our existing knowledge of Australia’s individual Marine Parks. This series is a product of the National Environmental Science Program Marine Biodiversity Hub Project D3, which seeks to determine the status of marine biodiversity assets on the continental shelf to inform monitoring of Australian Marine Parks. The South-west Corner Marine Park contains large areas of high biodiversity and benthic productivity, although most of the Marine Park still remains to be surveyed. The Park is defined by extensive plains across the continental shelf covered by mixed communities of macroalgae, seagrasses and sponges. Since these plains cover ~95% of the surveyed area, such communities account for a large proportion of benthic productivity and biodiversity in the region. Black and octocorals, hydroids and bryozoans are present in deeper areas of the continental shelf, while areas deeper than 120 m are mostly formed by soft sediments. A total of 140 fish species across 61 families were identified in the Marine Park, including several shark species and other commercially targeted species. The Park is also habitat for numerous seabirds and migratory passage for several cetacean species.