From a geographic, economic and social sense, the European Union (EU) is deeply impacted by seas and oceans. At the third United Nations (UN) Conference on the Law of the Sea, the concerns and positions presented by EU Member States were altogether heterogeneous. Such heterogeneity was due to their different maritime interests. Given the importance of the European Community (EC), it was granted observer status by the UN at the aforementioned conference, as well as signing and formally confirming the 1982 UN Convention on the Law of the Sea (LOS Convention) in 1984 and 1998, respectively. Through its participation in maritime-related UN special agencies and institutions founded under the framework of the LOS Convention, the EU has exerted greater influence on the progressive development of the international Law of the Sea. Within the EU legal regime, the LOS Convention serves as the legal basis for developing EU maritime and fisheries policies and regulations. This gives the EU a significant role in the development of regional maritime policy. While there are ambiguities regarding the competence between the EU and its Members States, the EU has made efforts in various maritime fields, such as Port State Control, fisheries management, participation of regional fisheries management organizations, marine environmental protection, maritime safety and security along with dispute settlement. Above all, given that the EU dispute settlement mechanism has binding force, it can improve its Member States’ compliance with the LOS Convention and increase the effectiveness of this set of rules.