The Western Bass Strait Shelf Transition is a biogeographic region of Australia's coastal and continental shelf waters. It is a transitional region between the cold-temperate Bass Strait Shelf and Tasmanian Shelf provinces and the warm-temperate Spencer Gulf Shelf Province. It is a provincial bioregion in the Integrated Marine and Coastal Regionalisation of Australia (IMCRA) system. It is the southern portion of the Western Bassian marine ecoregion in the World Wildlife Fund's (WWF) Marine Ecoregions of the World system.