Deben Estuary SSSI is a 981.1-hectare (2,424-acre) biological Site of Special Scientific Interest (SSSI) covering the River Deben and its banks 12 kilometres (7.5 miles) from its mouth north of Felixstowe to Woodbridge in Suffolk.

[1][3] It is a Ramsar internationally important wetland site[4][5] and a Special Protection Area under the European Union Directive on the Conservation of Wild Birds.

[6][7] It is also in the Suffolk Coast and Heaths Area of Outstanding Natural Beauty.

[9] The site has been designated an SSSI for its overwintering waders and wildfowl, and for its diverse saltmarshes.

It has internationally important overwintering redshanks and nationally important numbers of dark-bellied brent geese, shelducks and black-tailed godwits.