Since 2015, Polish foreign policy has witnessed a gradual rise in the significance of regional cooperation, as reflected in its enthusiasm for the Three Seas Initiative (TSI)1. The Initiative constitutes an in statu nascendi undertaking, one which aims to consolidate cooperation among states located in the region between the Baltic, Black, and Adriatic Seas. (In Poland, a popular acronym to denote the project is the “ABC initiative,” which reflects the Polish names of these bodies of water [i.e., Adriatyk, Bałtyk, Czarne]. However, itmust be emphasized that the member states of the TSI do not operate invacuum, but rather within a broader institutional framework that includes the European Union, the Central European Initiative, and the Visegrád Group. This paper begins by outlining the prospective geopolitical determinants that will determine the success or failure of the TSI, with particular attention paid to issues of regional security. It concludes by analysing how the Initiative may become a new model for regional cooperation.