A State situated at the edge of a marine area, exercising its legal and administrative jurisdiction over the marine areas adjacent to its territory in conformity with international law. In pursuance of international law, the coastal State exercises its sovereignty over its internal waters and territorial sea. It exercises sovereign rights or jurisdiction over its continental shelf and exclusive economic zone (EEZ), if it has established one (cf. Jurisdictionalisation).
In particular, international law enables the coastal State to regulate exploitation of the natural resources in its EEZ and on its continental shelf. To this purpose, it carries out controls on national or foreign vessels, and applies sanctions to those which violate its regulations. It is thus armed with all the necessary legal means to ensure compliance with conservation rules in these marine areas, even in the case of vessels not flying its flag. Unlike the case of the high sea, the exclusive jurisdiction of the flag State may not stand in the way of a control or sanctions applied to an offending party.
The guarantee of the effectiveness of conservation rules is thus higher in waters covered by the coastal State's jurisdiction than on the high sea. But it still remains that the material difficulties encountered in controlling vast marine areas do not guarantee compliance with rules and regulations (cf. Effectiveness of the law).