The present thesis explores the connection between international legal frameworks and renewable energy development in the marine sector, with an emphasis on the rules of the United Nations Convention on the Law of the Sea (UNCLOS). Exploiting renewable energy sources, such as offshore wind, tidal, and solar power, provides a viable substitute for fossil fuels, as climate change and energy security become major worldwide concerns. The exploitation of these resources, however, brings up complex legal issues pertaining to sovereignty, jurisdiction, and maritime environmental protection. As a coastal and energy-dependent Member State of the European Union, Greece finds itself at the intersection of significant legal, environmental, and geopolitical developments in the Eastern Mediterranean. Moving forward, the present thesis will aim to examine how the country navigates its commitments under EU and international law, while also seeking to exploit the potential of offshore renewable energy sources within a highly complex regional environment. Greece, with its extensive coastline and access to both the Aegean and the Ionian Seas, could benefit significantly from the expansion of offshore renewable energy. Nevertheless, longstanding maritime disputes, especially with Turkey, pose legal and political challenges to the realization of such projects. In this context, their implementation shall align with international maritime law, including the delimitation of the country’s exclusive economic zone and continental shelf, as well as relevant European Union directives on energy and environmental protection. The purpose of this thesis is to examine how the Law of the Sea governs the rights and obligations of coastal states in exploiting marine renewable energy sources, by addressing concerning issues such as transboundary disputes, environmental sustainability, and the balance between competing interests in maritime spaces. By analyzing the legal, environmental, and geopolitical dimensions of renewable energy development in Greece and the wider Mediterranean region, the study aspires to add on the broader dialogue on the role of international law in supporting sustainable energy transition.