This paper examines the state-of-play of Maritime Spatial Plans (MSP) in the EU through a case studies methodology in order to identify problems and prospects for the development of national and transnational MSP plans in the Eastern Mediterranean (Eastern Med). This research found that of the 22 EU countries which should have had MSP in place as of March 31, 2021, only 12 have approved plans and less than half are implementing them as of February 2022. The two European sea basins which have the greatest percentage of national MSP in place as well as evidence of transnational plans are the Baltic Sea and the North Sea. Meanwhile, the Eastern Med does not have any national maritime spatial plans in place and only preliminary evidence of cross-border planning efforts between Greece and Cyprus. In terms of best practices around transnational maritime spatial plan development, this research found the North Sea to be the most notable. Collaboration in the North Sea basin was largely driven by the spirit of blue growth and mutual economic interest, as opposed to sustainability and conservation, and the efforts were supported politically and economically by the EU and the countries involved. Using the case of the North Sea and the Commission-supported transboundary MSP development toolkits available, this research shows that the Eastern Med lacks even the most basic elements necessary for the development of transboundary MSP amongst EU member states, let alone with non-EU states. And, it asserts that the most important “next steps” for the region involve creating awareness of MSP in the region through a single authoritative platform, developing a political consensus over key issues, and solving protracted legal problems on the delimitation of maritime zones amongst EU and non-EU states. On account of the volatile nature of the region, the EU’s political reach and ability to influence non-EU member states to embrace MSP is expected to be both severely tested and key for the development of a holistic MSP framework in the Eastern Med.