This report is a contribution to the Strategic Environmental Assessment (SEA3) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). This report summarises the large number of existing conservation sites and potential sites of conservation importance in the SEA3 area of the North Sea. The SEA 3 area displays a wide variety of habitat types, from those of a coastal nature, such as estuarine mudflats and sandflats, saltmarsh, sea cliffs and reef habitats, to those associated with the offshore environment. Some of these habitats are rare in a national and/or international context, and many support important numbers of birds, insects and other animals. Existing coastal and nearshore conservation sites are protected by international, national and local conservation designations. Statutory sites are legally protected whilst non-statutory sites rely on the planning process to confer protection. The UK Government is currently taking steps to implement the EC Habitats Directive and the Birds Directive in offshore waters. A process to designate Special Areas of Conservation and Special Protection Areas, both within territorial waters and out to the limits of the UKCS, is under way. Potential offshore conservation sites are reviewed.