The coastline of the Northern Baltic sea constitutes of a mosaic of islands and bays with a very heterogeneous submerged landscape.The archipelago of Finland,Åland and Sweden is naturally nutrient rich and very productive with unique and species rich flora community.The shallow bays and shelterd archipelago areas are also important for the reproduction of a number of fish species and provide the foundation to entire food webs.The area with its characteristic nature gives refreshment for the visitors and incomes for the inhabitants; the human activity is also consentrated on shallow basins.A prerequisite for sustainable planning of the area is to know the special characters of the underwater nature. Nature values are taken into account in usage of terrestrial environments, but unfortunately there is a lack of basic tools and co-opetarion between experts and stakeholders in the marine environment. The project aims to protect the underwater nature of the Northen Baltic archipelago and coastal areas by improving the facilities to implement sustainable planning. The outcomes (methods, best-practices, innovative tools, experiences) can be applied also in other Central Baltic areas. The project aims to increase sustainable infrastructure by firstly, developing and testing locally optimal methods for collecting and processing underwater data and secondly, by adapting the usage of underwater information in stakeholders ordinary work.The objective will be reached with three WPs: 1) Management of the project and dissemination of project results within partners and stakeholders, 2) Development of tools to collect and illustrate the underwater information, 3) Integrating the usage of the underwater information into solid part of environmental management on all levels of administration and public usage. The key stakeholders of the project are a) the municipal officers and authorities on a regional level responsible for the planning of land use and sustainable use of natural resources, b) the organisations conducting the inventories and processing the data with methods tested by other partners in the project and c) visitors and inhabitants exploiting and enjoying the target area. The project will improve the quality of knowledge about submerged nature in general and ensure the sustainable usage of it. The objective will be reached in practise with examplary actions and novel case studies in WP3. With these examplary co-operations of experts and stakeholders the best practices and experiences for utilization of the underwater data will be assimilated in policymaking. The results of these case studies will be disseminated to other statekholder as well. Interdiciplinary co-operation and cross-border actions essentially increase the knowledge of best practises in spatial planning and land use of the target area. Achievements: NANNUT highlighted the importance of underwater natural values (habitats and species) to local decision makers and the general public. The project organised a series of stakeholder seminars both for local politicians and other main target groups such as planners. In addition, and as one of the the main project result, the project produced a web portal (www.nannut.fi) containing data sets and maps about valuable areas in the project area. NANNUT also focused on outreach activities and produced a DVD describing important nature types under the surface.