This thesis examines the process applied by international tribunals for delimiting Exclusive Economic Zone (EEZ) and continental shelf boundaries under international law. Maritime delimitation is governed by articles 74 and 83 of the 1982 UN Convention on the Law of the Sea (UNCLOS), which are customary international law. However, owing to the vagueness of such legal provisions, international tribunals have been developing a standard process for delimiting maritime boundaries. The delimitation process has evolved significantly since the 1969 judgment of the International Court of Justice (ICJ) in North Sea Continental Shelf. The ICJ re-stated this process in its 2009 Black Sea judgment as being constituted of three stages: first, an equidistance line is provisionally drawn; second, this line is adjusted should relevant circumstances so require; third, the overall equitableness of the boundary is evaluated by assessing the proportionality between the length of the relevant coast and the marine areas appertaining to each state. This thesis analyses each stage of the delimitation process as re-stated in Black Sea. By way of introduction, chapter 1 outlines the relevant legal provisions and the historical evolution of the delimitation process through the jurisprudence of international tribunals. Chapter 2 discusses both the notions of the relevant coast and of the relevant area, and the practical methods for their identification. Since Black Sea, international tribunals have tended to identify the relevant coast and the relevant area prior to establishing a provisional equidistance line. Chapter 3 discusses the issues concerning the drawing of the provisional equidistance line. Chapter 4 examines relevant circumstances and the methods for adjusting an equidistance line. Chapter 5 discusses proportionality. Using doctrinal legal research methodologies, this thesis aims to assess the degree of consistency in the international tribunals’ application of the three-stage delimitation process. It argues that, while great leaps forward have been made since 1969, there is still a number of unresolved issues, in relation to which this thesis endeavours to provide some workable solutions.