The Walberswick section of the reserve is the largest at . It contains a range of habitats including reedbed, hay meadows, grazing marshes, heather and grass heathlands and a variety of mixed and broadleaved woodlands. Along the coast shingle banks and beaches, saline lagoons and intertidal estuary and saltings are also present, providing a range of fresh, brackish and salt water habitats, whilst the area along the Blyth estuary provides mudflats and grazing marsh.
