The Gulf of Bothnia and Archipelago area are shared by Finland, Åland, and Sweden. These waters are fraught with planning challenges and cross-border interactions, as well as a myriad of land-sea-interactions. The goal of the FIAXSE activity was to develop the tools and knowledge needed to make sure that the shared sea and unique environments can be preserved, while at the same time promoting the possibilities that the blue economy brings. Multiple Blue-Economy sectors are dependent on the Gulf of Bothnia, and the Archipelago areas, for their income. As MSP planners, finding multi-sea use possibilities and finding solutions for co-existence are some of the key-challenges that planners face when planning for the future. Increasing collaboration cross-border, cross-level, and cross-sectoral can help to find solutions for better plans in the future.