Tucked behind the northern section of Wilsons Promontory, Corner Inlet Marine National Park (1,150 ha) sits within the sheltered waters of Corner Inlet. Corner Inlet is the most easterly, and consequently the warmest, of Victoria's large embayments.     

Corner Inlet Marine National Park is made up of two separate portions with a channel between them. Granite Island borders the boundary of the northern section while Bennison Island borders the boundary of the southern section.  

The park protects a wide variety of marine habitats ranging from deep channels to extensive shallow seagrass beds, tidal sand and mud flats, sandy beaches, and some rocky reefs, mangroves and saltmarsh. 

Corner Inlet is the only place in Victoria where the Broad-leaved Seagrass (posidonia australis) forms large meadows including within the Marine National Park. Seagrass beds are a crucial habitat as a nursery for many important recreational and commercial fish species, in stabilising the sediment, and in providing shelter and food for many other creatures.  

Corner Inlet Marine National Park support healthy populations of seafloor animals and plants that are rare or absent elsewhere in Victoria. Animals in the park include a range of large crabs, multicoloured seastars, sea snails, tiny iridescent squid, and many fish including Pipefish, Stingarees, Flathead, Whiting, and Flounder all live within the seagrass.  

Corner Inlet Marine National Park also supports large numbers of migratory wader birds The park is especially significant for over-wintering migratory wading birds and supports 20 per cent of Victoria’s total wader population. The park forms part of the Corner Inlet Ramsar Site and is recognised as a wetland of international significance under the Ramsar Convention and is part of the East Asian-Australasian Flyway for migratory wader birds.  

These tranquil waters provide an excellent setting for a range of boat based recreational activities from power boating, sailing, to canoeing and kayaking. Beneath the water snorkellers and divers can experience a diverse range of marine life within the seagrass community.