Great Oyster Bay is a broad and sheltered bay on the east coast of Tasmania, Australia which opens onto the Tasman Sea. The Tasman Highway runs close to the West Coast of the bay with views of the granite peaks of the Hazards and Schouten Island of the Freycinet Peninsula which are incorporated in the Freycinet National Park.
Towns on the bay include Swansea and Coles Bay.
At the north of the bay the floodplains of the Aspley and Swan rivers has created Moulting Lagoon, an important Ramsar-listed wetland, much of which lies in the Moulting Lagoon Game Reserve.[1] Nearby is the Friendly Beaches Reserve owned and managed by Bush Heritage Australia (BHA).