Knettishall Heath is a 91.7 hectare biological Site of Special Scientific Interest west of Knettishall in Suffolk. A larger area of 176 hectares is the Knettishall Heath Nature Reserve, which is managed by the Suffolk Wildlife Trust.
Suffolk Wildlife Trust (SWT) describes itself as the county's "nature charity – the only organisation dedicated wholly to safeguarding Suffolk's wildlife and countryside." It is a registered charity, and its headquarters is at Brooke House in Ashbocking, near Ipswich. It was founded in 1961, and is one of 46 wildlife trusts covering the Great Britain and Northern Ireland. As of March 2017, it has 13,200 members, and it manages 3,120 hectares of land in 60 nature reserves, most of which are open to the public. It had an income of £3.9 million in the year to 31 March 2017.
Rex Graham Reserve is a 2.8 hectare biological Site of Special Scientific Interest east of Mildenhall in Suffolk. It is a Special Area of Conservation, and part of the Breckland Special Protection Area. It was formerly managed by the Suffolk Wildlife Trust.
Lackford Lakes is a 105.8 hectare biological Site of Special Scientific Interest (SSSI) north and east of Lackford in Suffolk. The SSSI is part of the 131 hectare Lackford Lakes nature reserve, which is managed by the Suffolk Wildlife Trust.
Alde–Ore Estuary is a 2,534 hectare biological and geological Site of Special Scientific Interest which stretches along the Suffolk coast between Aldeburgh and Bawdsey, and also includes parts of the Alde, Ore and Butley Rivers. It is in the Suffolk Coast and Heaths Area of Outstanding Natural Beauty, and is a Grade I Nature Conservation Review site, a Special Area of Conservation, a Ramsar internationally important wetland site, and a Special Protection Area under the European Union Directive on the Conservation of Wild Birds. It includes two Geological Conservation Review sites, "Orfordness and Shingle Street" and "The Cliff, Gedgrave", and two nature reserves managed by the Suffolk Wildlife Trust, Alde Mudflats and Simpson's Saltings. The coastal part of the site is Orfordness-Havergate, a National Nature Reserve, and Orford Ness is managed by the National Trust, while Havergate Island is managed by the Royal Society for the Protection of Birds.
Groton Wood is a 20.2 hectare biological Site of Special Scientific Interest north-east of Groton in Suffolk. It is owned and managed by the Suffolk Wildlife Trust.
Bradfield Woods is an 81.4 hectare biological Site of Special Scientific Interest between Bury St Edmunds and Stowmarket in Suffolk. The site is in three separate blocks, the adjoining Felsham Hall and Monkspark Woods, and the much smaller separate Hedge Wood and Chensil Grove. Felsham Hall and Monkspark Woods are designated a 63.3 National Nature Reserve, also called Bradfield Woods, and are managed by the Suffolk Wildlife Trust.
Mickfield Meadow is a 1.9 hectare biological Site of Special Scientific Interest north of Mickfield in Suffolk. It is managed by the Suffolk Wildlife Trust.
Wangford Warren and Carr is a 67.8 hectare biological Site of Special Scientific Interest between Brandon and Lakenheath in Suffolk. It is a Nature Conservation Review site, Grade I, and part of the Breckland Special Area of Conservation, and Special Protection Area An area of 15 hectares is managed as a nature reserve by the Suffolk Wildlife Trust
Combs Wood is a 15.1 hectare biological Site of Special Scientific Interest on the southern outskirts of Stowmarket in Suffolk. It is owned and managed by the Suffolk Wildlife Trust.
Sizewell Marshes form a 260-acre biological Site of Special Scientific Interest adjacent to Sizewell in Suffolk. It is in the Suffolk Coast and Heaths Area of Outstanding Natural Beauty, and is part of a 356-acre (144-ha) nature reserve managed by the Suffolk Wildlife Trust as Sizewell Belts.
Fox Fritillary Meadow is a 2.4 hectare biological Site of Special Scientific Interest north of Framsden in Suffolk. It is owned and managed by the Suffolk Wildlife Trust.
Hopton Fen is a 15.3 hectare biological Site of Special Scientific Interest north of Hopton in Suffolk. It is managed by the Suffolk Wildlife Trust.
Blo' Norton and Thelnetham Fens are a 21.3 hectare biological Site of Special Scientific Interest (SSSI) on the Norfolk/Suffolk border. Blo' Norton Fen is in the parish of Blo' Norton in Norfolk and Thelnetham Fen is in Thelnetham parish in Suffolk. It is a Nature Conservation Review site, Grade 2, and part of the Waveney and Little Ouse Valley Fens Special Area of Conservation, Thelnetham Fen is managed by the Suffolk Wildlife Trust and Blo' Norton Fen by the Little Ouse Headwaters Project (LOHP).
Sutton and Hollesley Heaths is a 483.3 hectare biological Site of Special Scientific Interest south-east of Woodbridge in Suffolk. Most of the site is managed by the Suffolk Wildlife Trust as Sutton and Hollesley Commons. It is part of the Sandlings Special Protection Area under the European Union Directive on the Conservation of Wild Birds, and the Suffolk Coast and Heaths Area of Outstanding Natural Beauty.
Metfield Meadow is a 1.3 hectare biological Site of Special Scientific Interest west of Halesworth in Suffolk. It is owned and managed by Suffolk Wildlife Trust under the name Winks Meadow.
Barking Woods is a 98.7 hectare biological Site of Special Scientific Interest in six separate blocks north-east of Ipswich in Suffolk. Part of it is a 20 hectare nature reserve called Bonny Wood, which is owned and mangaged by the Suffolk Wildlife Trust.
Weston Fen is a 49.7 hectare biological Site of Special Scientific Interest in Hopton in Suffolk. It is part of the Waveney and Little Ouse Valley Fens Special Areas of Conservation, and an area of 37 hectares is managed as a nature reserve called Market Weston Fen by the Suffolk Wildlife Trust.
Thorpe Morieux Woods is a 45.2 hectare biological Site of Special Scientific Interest north of Thorpe Morieux in Suffolk. Part of it is Bull's Wood, a nature reserve managed by the Suffolk Wildlife Trust.
