The article evaluates the modern doctrine of territorial sea administration. The article views the administration of coastal state as an application and enforcement of UNCLOS based regimes of maritime zones. The article examines the legal regulation of the territorial sea. It also studies the process of overlapping and interaction between different administrative and legal regulations applicable to a given maritime zone. The features of such regulation are pointed out based upon the combination and mutual influence of international, EU and national law. Ukraine’s experience in administering the territorial sea after the illegal annexation of Crimea is studied. The pros and cons of EU concept of Maritime spatial planning with respect to the demands of protection and security are revealed in the context of hybrid conflicts.