Providing a comprehensive analysis of the current legal basis for the establishment and further development of area-based conservation tools in the Mediterranean Sea, this book explores provisions under international law and the relevant region frame works to explore transboundary marine protected areas (MPAs) and other effective area-based conservation measures (OECMs) implemented at sub-regional level. Under the European Union’s 2030 Biodiversity Strategy, EUmember States will be responsible for designating the additional protected and strictly protected areas, either by expanding or completing the so-called ‘NATURA 2000’ Network or under national protection schemes through the establishment of national MPAs, including possible transboundary MPAs and OECMs established in accordance with the provisions of the relevant regional seas conventions. This book provides a discussion of the juridical status of the Adriatic and Ionian Seas as parts of a wider enclosed or semi-enclosed Mediterranean Sea, followed by an assessment of the interrelation between global, regional, sub-regional and national legal frameworks on MPAs and OECMs. It offers a comprehensive analysis of the legal basis regarding the establishment of national and, where appropriate, transboundary MPAs and OECMs. Discussing relevant examples of good practice related to transboundary and MPAs, the book will provides an overview of the challenges and opportunities related to the establishment of a transboundary Mediterranean Specially Protected Area of Mediterranean Importance (SPAMI), based on the provisions of the relevant Protocol to the Barcelona Convention, as well as on the challenges and opportunities related to the establishment of a transboundary international marine park and on the feasibility of the establishment of one or more Particularly Sensitive Sea Areas (PSSAs) within the Adriatic and Ionian Seas, and beyond. The book will be of interest to policy makers, practitioners and academics with an interest in public international law, law of the sea and sustainable ocean governance.