Since the failure of the 1958 and 1960 Conferences on the Law of the Sea to provide for universally agreed outer limits of the territorial sea, international law has been faced with numerous claims on a seaward extension of coastal State jurisdiction. Such national claims have taken two different forms, either by making the claimed area part of the State territory, or by merely asserting certain exclusive rights and regulatory powers in given marine zones. The scope and content of such zonal claims vary considerably, according to the particular objective pursued. This development reached its peak between 1976 and 1979. In this four year period, 60 claims were made regarding territorial seas and 59 claims were made to establish exclusive economic zones. That phenomenon is, at least partly, the consequence of the negotiations of the Third UN Conference on the Law of the Sea. In May 1975, following the second substantive session, the Conference produced its first negotiating text. It reflected a general consensus on, inter alia, a 12 mile extension of the territorial sea and the acceptance, in principle, of a 200 mile exclusive economic zone. Meanwhile the Convention on the Law of the Sea (CLOS) has been signed by 157 States and ratified by 31. Such a large number of States giving their assent to the Convention leads to the question of how far national claims to archipelagic waters, extended territorial seas, exclusive economic zones or extended continental shelf areas, are compatible with the Convention on the Law of the Sea. The message provided by such an analysis of State practice will be twofold. It firstly indicates whether the Convention on the Law of the Sea was successful in putting an end to the permanent extension of coastal State jurisdiction experienced in the past and whether it thus contributed to the reduction of potential conflicts concerning the distribution of the resources of the sea. In this respect the Third UN Conference on the Law of the Sea and its result, the Convention on the Law of the Sea, have to be subject to an appraisal against the background of Article 13 paragraph 1(a) UN Charter, according to which it is one of the functions of the General Assembly to promote and encourage the progressive development of international law as a means of maintaining international peace and security.