Belgium became officialy a federal state in 1993. The federal competence was reshuffeled and parts of it attributed to the Communities and Regions. Since the latter became competent in economic matters, it is mostly the redistribution of powers between the federal and regional level which is at order in this study. At first sight, a rather simple rule of thumb can be applied. All waters located on the land-side of the baseline, i.e. the low-water line in Belgium, belong to the competence of the Regions. All waters on the seaside of the baseline, on the other hand, remain a federal competence. This is the result of a basic interpretation given by the Conseil d’Etat in 1976. This body reached the conclusion that the territorial sea did not form part of the Belgian territory. Since the geographical situation is such that only one province borders the sea in Belgium, this interpretation was welcomed by the government at a time when the first steps of the federalization were being worked out. The territorial sea thus remained a federal competence, and the other maritime areas on the sea-side of the baseline followed this example. The application of this criterion of the baseline, it should be noted, sometimes leads to tensions between the federal and the regional authorities, as evidenced by the control of the quality of swimming water. But exceptions to this basic rule exist. First of all, a certain competence on the sea-side of the baseline has been attributed to the Flemish Region, such as the competence regarding pilotage, buoyage and towing at sea. Also the financial support of the fishing industry was regionalized. Secondly, the government has indicated its willingness to transfer certain other parts of its competence with respect to the exploration and exploitation of the natural resources of the territorial sea and the continental shelf. Even though this commitment was made in 1980, as of today no implementation has followed. Thirdly, new tendencies can be discerned. Recent opinions delivered by the Conseil ...