The Southern North Sea is bordered by Great-Britain, France, Belgium, The Netherlands, Germany and Denmark. The North Sea basin and its adjacent shorelines are intensively used. Management of the basin and the coastal zone is therefore essential. Because of the small scale of the area, the dense population and the big scale of the interactions, international cooperation is vital. In this paper an overview is given of both the morphologic-physical interactions and the administrative interactions between the bordering governments. A complicating factor in Coastal Zone Management around the Southern North Sea is that CZM is highly connected to national spatial planning and to sea defence policy. In several of the bordering countries this is not a subject of the national government, but is handled on a regional level. This makes that we are dealing with more authorities involved. At this moment international agreement exists on most aspects of active use of the North Sea basin itself (navigation, oil and gas mining, fishery, cables, etc) and its major coastal shallow areas (like the Waddensea). However in the field of passive use (pollution by inflowing rivers, air contamination by heavy industry, risk by transport and processing of hazardous goods) still much has to be done. International agreement on the recreation along the coastal strip does not yet exist. Also the standards for coastal protection against flooding by storm surges and against chronic erosion vary in each country.