A site of special scientific interest (SSSI) in Great Britain, or an area of special scientific interest (ASSI) in the Isle of Man and Northern Ireland, is a conservation designation denoting a protected area in the United Kingdom and Isle of Man. SSSI/ASSIs are the basic building block of site-based nature conservation legislation and most other legal nature/geological conservation designations in the United Kingdom are based upon them, including national nature reserves, Ramsar sites, Special Protection Areas, and Special Areas of Conservation. The acronym "SSSI" is often pronounced "triple-S I".
Allt Pontfaen - Coed Gelli-fawr is a Site of Special Scientific Interest in Pembrokeshire, South Wales which starts at Allt Pontfaen and finishes at Coed Gelli-fawr. It has been designated as a Site of Special Scientific Interest since January 1954 in an attempt to protect its fragile biological elements. The site has an area of 73.12 hectares and is managed by Natural Resources Wales.
Castlemartin Corse is a Site of Special Scientific Interest in Pembrokeshire, South Wales. It has been designated as a Site of Special Scientific Interest since February 1985 in an attempt to protect its fragile biological elements. The site has an area of 30.4 hectares and is managed by Natural Resources Wales.
Corsydd Llangloffan is a Site of Special Scientific Interest in Pembrokeshire, South Wales. It has been designated as a Site of Special Scientific Interest since February 1992 in an attempt to protect its fragile biological elements. The site has an area of 56.7 hectares and is managed by Natural Resources Wales.
Cwm Bach, Sychpant is a Site of Special Scientific Interest in Pembrokeshire, South Wales. It has been designated as a Site of Special Scientific Interest since February 1989 in an attempt to protect its fragile biological elements. The site has an area of 8.67 hectares and is managed by Natural Resources Wales.
Cwm Dewi is a Site of Special Scientific Interest in Pembrokeshire, South Wales. It has been designated as a Site of Special Scientific Interest since January 2010 in an attempt to protect its important geological elements. The site has an area of 22.02 hectares and is managed by Natural Resources Wales.
Dowrog Common is a Site of Special Scientific Interest in Pembrokeshire, South Wales. It has been designated as a Site of Special Scientific Interest since January 1954 in an attempt to protect its fragile biological elements. The site has an area of 0.18 hectares and is managed by The Wildlife Trust of South & West Wales.
Dwrhyd Pit is a Site of Special Scientific Interest in Pembrokeshire, South Wales. It has been designated as a Site of Special Scientific Interest since January 1957 in an attempt to protect its fragile geological elements. The site has an area of 0.18 hectares and is managed by Natural Resources Wales.
Dyffryn Gwaun is a Site of Special Scientific Interest (SSSI) in Pembrokeshire, South Wales. It has been designated as a Site of Special Scientific Interest since January 1954 in an attempt to protect its fragile biological elements. The site has an area of 25.36 hectares and is managed by Natural Resources Wales.
Esgyrn Bottom is a Site of Special Scientific Interest in Pembrokeshire, South Wales. It has been designated as a Site of Special Scientific Interest since January 1957 in an attempt to protect its fragile biological and geological elements. The site has an area of 49.9 hectares and is managed by Natural Resources Wales.
Felin Llwyngwair is a Site of Special Scientific Interest near Newport in Pembrokeshire, South Wales. It was designated a SSSI in October 2000 to protect its fragile biological elements. The site has an area of 0.01 hectares and is managed by Natural Resources Wales.
Gallt Llanerch - Coed Gelli-deg is a Site of Special Scientific Interest in the Gwaun Valley, Pembrokeshire, South Wales. It has been designated as a Site of Special Scientific Interest since January 1954 in an attempt to protect its fragile biological elements. The site has an area of 30.47 hectares and is managed by Natural Resources Wales.
Jeffreyston Pastures is a Site of Special Scientific Interest in Pembrokeshire, South Wales. It has been designated as a Site of Special Scientific Interest since January 1996 in an attempt to protect its fragile biological elements. The site has an area of 15.72 hectares and is managed by Natural Resources Wales.
Newport Cliffs is a Site of Special Scientific Interest lying a little to the north of Newport in Pembrokeshire, South Wales. It has been designated as a Site of Special Scientific Interest since January 1954 in an attempt to protect its fragile biological elements. The site has an area of 48.23 hectares and is managed by Natural Resources Wales.
Park House Outbuildings, Stackpole is a Site of Special Scientific Interest in Pembrokeshire, South Wales, 4 kilometres (2.5 mi) south of Pembroke, and is of special interest as the largest known nursery roosts of lesser horseshoe bats Rhinolophus hipposideros in Pembrokeshire. It has been designated as a Site of Special Scientific Interest since February 1998 in an attempt to protect its fragile biological elements. The site has an area of 0.01 hectares and is managed by Natural Resources Wales.
Stackpole Quay - Trewent Point is a cliff on the Castlemartin Peninsula of South Pembrokeshire, South Wales and is a Site of Special Scientific Interest (SSSI). It has been designated as a SSSI since January 1977 in an attempt to protect its fragile biological and geological elements. The site has an area of 64.15 hectares and is managed by Natural Resources Wales.
Strumble Head - Llechdafad Cliffs is a Site of Special Scientific Interest (SSSI) in Pembrokeshire, South Wales. It has been designated as a SSSI since January 1954 in an attempt to protect its fragile biological and geological elements.
Trefeiddan Moor is a Site of Special Scientific Interest in Pembrokeshire, South Wales. It has been designated as a Site of Special Scientific Interest since January 1966 in an attempt to protect its fragile biological elements. The site has an area of 21.61 hectares and is managed by Natural Resources Wales.
Treffgarne Bridge Quarry is a Site of Special Scientific Interest in Pembrokeshire, South Wales. It has been designated as a Site of Special Scientific Interest since January 1954 in an attempt to protect its fragile geological elements. The site has an area of 0.4 hectares and is managed by Natural Resources Wales. The name derives from the Welsh "Trefgarn".
Wyndrush Pastures is a Site of Special Scientific Interest south-east of the village of Redberth, just south of the A477, and around five km (3.1 mi) to the north-west of the coastal town of Tenby in Pembrokeshire, South Wales. It has been designated as a Site of Special Scientific Interest since October 1999 in an attempt to protect its fragile biological elements. The site has an area of 45.5 hectares and is managed by Natural Resources Wales.
