Langstone Harbour is a 2,085.4-hectare (5,153-acre) biological Site of Special Scientific Interest in Hampshire. It is an inlet of the English Channel in Hampshire, sandwiched between Portsea Island to the south and west, Hayling Island to the south and east, and Langstone to the north. It is part of the Ramsar site of Langstone and Chichester Harbour Special Protection Area and Nature Conservation Review site. Parts are Special Areas of Conservation, or Local Nature Reserves, and some areas by the Hampshire and Isle of Wight Wildlife Trust.