The Oslofjord faces severe ecosystem deterioration due to pollution, runoff, overfishing, and coastal developments. The area is governed by multiple authorities, requiring complex cross-sectoral and territorial coordination. While River Basin Management offers a cross-sectoral approach, it focuses on freshwater, lacks marine indicators, and excludes sectors like fisheries. Municipal spatial plans, while crucial for land-based activities impacting the fjord, rarely regulate the use of the fjord itself. While Norway has ecosystem-based management plans for its oceans, these do not sufficiently consider coastal areas. This case study examines the implementation and interaction of these policies and tools to identify governance gaps and improve the situation in the Oslofjord.