With an ambitious partnership between fifteen regions from the UK, France, Belgium and the Netherlands SAIL II (Schéma dAménagement Intégré du Littoral) is a transnational endeavour seeking to foster greater cooperation between maritime regions over three years. It aims to promote territorial integration between a triangle of coastal regions, including estuaries, in the Southern North Sea Area. Whilst many cooperation programmes have involved the northern North Sea regions, this project would seem to plug a crucial gap by promoting action between the eastern English Channel and lower North Sea. Starting from the solid foundations laid down through Interreg IIC where partners developed an innovative coastal zone management (ICZM) to the multiple issues relevant to this busy maritime region, this IIIB project will tackle administrative, political and economic deficits. Its objective is to encourage greater participation in joint policy formulation and implementation, in part by creating a political platform for exchange and cooperation and harmonising informational resources, in order to improve common understanding and provide more effective tools for decision-makers. Ultimately, however, the impacts of these measures will benefit the citizen through reducing the polarisation of deprived coastal communities, improving links with the more prosperous hinterlands and putting a halt on the degradation of the natural environment. The project embodies the concept of transnationality by bringing together all the relevant regional authorities to find innovative solutions to common maritime problems, recognising the fact that the sustainability of coastlines in the lower North Sea depends on coordinated approaches between all parties directly concerned. Achievements: First, the project developed a methodology for measuring the sustainable development of coastal regions that has been adopted on a European scale via the European Commission Expert Group on Integrated Coastal Zone Management. Second, SAIL is (reasonably) well-known among stakeholders as the principal voice for martime co-operation in the Southern North Sea. Third, actual impacts have been felt most noticeably on the ground where local investments in raising awareness, protecting and enhancing local environments, and tackling regeneration have been in many cases both profound and catalytic