Pitt Water-Orielton Lagoon is a tidal salt water lagoon with a narrow entrance to the sea, which includes the estuaries of four rivers. The Site comprises the uppermost parts of a wave-dominated barred estuary. The principal features are the channel and mouth of the Coal River estuary, Orielton Lagoon, a large embayment now almost closed by a causeway, and an extensive area of open marine waters. The Site supports a diversity of coastal, intertidal and marine habitats and communities, and is therefore a species-rich environment. In particular, it is considered important for conservation of coastal birdlife at the bioregional scale. Most of the wetland is fringed by saltmarsh vegetation and rocky shores. The Site supports a range of globally threatened species such as the critically endangered swift parrot (Lathamus discolor), the endangered Tasmanian wedge-tailed eagle (Aquila audax fleayi) and the far eastern curlew (Numenius madagascariensis); it also supports large numbers of the endemic Tasmanian viviparous sea-star (Patiriella vivipara). Extensive oyster farming operations occur within the Site and the surrounding area is used for livestock grazing. The Site continues to be important for the local Aboriginal community.