The Baltic Sea is one of the most polluted brackish water bodies in the world. Its most serious ecological threat is eutrophication caused by high nutrient loading of both point source and scattered loading from the catchment area. Intergovernmental and national legal obligations, treaties etc. have not been enough to improve the state of the Baltic Sea. On the other hand, cities and other local actors have a major influence to the sea both directly through their actions and indirectly via e.g. planning and co-operation. Global climate change will presumably increase the occurrences of extreme weather conditions, agricultural loading and the risk of flooding in cities thus resulting in even heavier nutrient loading to the Baltic Sea. This situation requires local level actors to achieve knowledge, new skills and tools in order to be better able to contribute to improving the environmental state of the Sea and to the preparedness level of their areas. In the summer 2007, the mayors of Helsinki and Turku in Finland committed themselves to saving the Baltic Sea. The joint action plan of these two cities puts into practice voluntary measures which have an influence on the state of the local waters as well as on the entire Baltic Sea by reducing loading and promoting such management and operations that enhance water protection in the city administration. In addition to shaping up their own performance, the cities of Helsinki and Turku have continued by challenging other actors to do the same. The challenge campaign has been a success in Finland. More than 160 participants (municipalities, universities, NGO’s, shipping companies etc.) have now committed to the campaign and many of them have written their own action plans. These good results in Finland inspire to spread this model of best practices around the Central Baltic Sea Region as cross-border cooperation is a necessity to have a wider impact on the state of the Baltic Sea. The overall objective of the project is to improve the state of the local waters and the entire Baltic Sea by implementing water protection measures on a voluntary basis (actions not required by the law) in the local level by municipalities and other actors. The immediate objective of the projects is to strengthen the commitment of the partners in water protection work and to give them tools to introduce water protection aspects to their every-day functions, administration and decision-making processes. They will also have a functioning model to continue the work after the project period has ended. Activities include educational seminars and workshops, study exchange for civil servants, producing manual of best practices for the municipalities and other local level actors. Project consists of 5 WP's: WP1 Management WP2 Preparation of action plans WP3 Awareness raising and producing infomaterial WP4 Joint platform for decision makers and experts and WP5 Investment ideas. Achievements: The Baltic Sea Challenge project improved the state of the Baltic Sea by implementing water protection measures on a voluntary basis at a local level. The project created tools to introduce water protection aspects into everyday functions within the city administration and decision-making processes at local level. The project focused on the challenges and opportunities in the field of eutrophication. Furthermore, the project encouraged new actors such as cities and municipalities, NGOs and schools to participate in the protection of the Baltic Sea. The project partners promoted and implemented voluntary action plans for the recovery of the Baltic Sea, prepared investment plans, carried out awareness-raising activities such as cross-border seminars, working groups, training sessions, high-level round-table discussions, a quiz for children and also organised a Baltic Sea art workshop.