It lies on Tasmania's north coast, adjoining Bass Strait, between Port Sorell in the west and the mouth of the Tamar River in the east.

Narawntapu encompasses islands in the Port Sorell estuary and the Carbuncle, as well as land extending to low water mark, including intertidal mudflats.

[1] Vegetation communities represented in the park include coastal heathland, dry sclerophyll woodland, herbland, grassland and salt marsh.

The birdlife is rich and includes threatened species such as the hooded plover, Tasmanian wedge-tailed eagle and swift parrot.

At certain times of the year, several species of ducks, as well as herons, swans, cormorants, coots, bitterns and grebes call the lagoon home.