Seal Sands (grid reference NZ529260) is a 294.37 hectare biological Site of Special Scientific Interest in County Durham, England, notified in 1966. Situated in the mouth of the River Tees next to Greatham Creek and Seaton-on-Tees Channel, the site is accessible from the A178 road running between Seaton Carew and Port Clarence. An area of reclaimed land is given over to chemical industries.