What is the entire framework for the Eastern Mediterranean Sea's delimitation borders, and how do emerging energy developments contribute to diplomatic debate on delimitation agreements? The present thesis seeks to provide an in-depth response to an issue that has dominated diplomatic and geopolitical discourse. First, the thesis provides a comprehensive overview of the legal framework governing maritime zones under the Law of the Sea. Beginning with the baselines, the thesis analyzes the core maritime zones directly related to the exploration and exploitation of energy resources, including the Territorial Sea, the Continental Shelf, and the Exclusive Economic Zone (EEZ). After this overview, the thesis provides an in-depth analysis of the broad concept of maritime zones delimitation (Articles 74.1 & 83.1 of UNCLOS). In the second unit, the thesis presents the case of the delimitation agreements in the Eastern Mediterranean Sea reached by Greece, Cyprus, Egypt, Turkey, Libya, Israel, and Lebanon, from the delimitation agreement of the EEZ of Cyprus and Egypt (2003) until Israel's newly signed delimitation agreement of maritime boundaries with Lebanon (2022). In the third unit, an overview of energy developments in the Eastern Mediterranean Sea is addressed, beginning from the analysis of the energy profiles of Egypt, Israel, Cyprus, and Greece, reaching the new topic of the Energy Transition in the Eastern Mediterranean which aims to highlight a new orientation for cooperation and energy diplomacy among the concerned States along the path toward climate neutrality. In conclusion, the present thesis indicates that the delimitation of maritime boundaries in the Eastern Mediterranean Sea is a practical matter for the concerned states to maximize the prize of energy resources and their developing potential.