Site overview: This is a small island about 18 km west of the mainland coast of south-west Wales which is home to large numbers of breeding seabirds. Grassholm (pictured from a distance above) often appears white in colour. This is due to the colour of the gannets that live there and their guano! This is an important place for gannet which breed here.

Designation Status
Last Updated
6 June 2017
MPA Type
Special Protection Area
MPA Purpose
areas of the most important habitat for rare (listed on Annex I to the Directive) and migratory birds within the European Union


51° 43' 57" North,
5° 28' 46" West

Surface Area

17.43 km2
(6.73 mi.2 )

Iconic features protected by this site


  • Marine areas, Sea inlets
  • Tidal rivers, Estuaries, Mud flats, Sand flats, Lagoons (including saltwork basins)


  • Northern gannet (Morus bassanus) (Regularly occurring migratory species)


  • Seabird assemblage