The North Sea is both an environmental asset and a source for value generation for different maritime sectors. Maritime Spatial Planning (MSP) is a tool to help balance the often competing user interests as well as environmental protection aims. However, MSP can only be effective, if national Maritime Spatial Plans are coordinated and not contradictory. A lack of MSP coordination leads to spatial inefficiencies, higher costs for maritime industries and compromised environmental objects. NorthSEE launches a sea-basin wide coordination process among MSP authorities in the North Sea Region (NSR). In this context, NorthSEE aims at achieving greater coherence in MSP across the NSR for three transnational topics: environmental aspects, shipping routes and energy infrastructure. Planners compare existing national MSP plans and approaches. In addition, future scenarios are jointly developed by planners and stakeholders in the framework of the “MSP Challenge 2050” simulation. This improved informational basis allows planners to identify current and future synergies and mismatches of national planning solutions and approaches as well as to come to planning solutions for selected sites with incompatibilities. Findings are synthesised in reports and maps. These will inform national MSP processes, whereby increased MSP coherence will be reached. Recommendations on an MSP coordination process in the NSR set the basis for an ongoing transnational MSP dialogue beyond the project’s lifetime.