At the current stage, there is no doubt about the role of the "Three Seas" initiative in the regional schedule. However, it is worth noting that one of the impetuses for its actualization was the world confrontation that arose after Russia's encroachments on the territory of Ukraine (the annexation of Crimea and the instigation of the war in the East of Ukraine). Today, this idea of unification of states in the space from the Baltic to the Black and Adriatic seas, as it was at its inception, is actively supported by the USA. Over the past eight years, the attitude towards this program on the part of Germany and the European Union has also changed in a positive direction. In fact, from Poland's attempt to realize its historical Central European ambitions, the Three Seas initiative was transformed into a prototype of the new Eastern Europe as an integral part of the transatlantic community. The interest of modern Polish politicians in the concept of "Mizhmorya" is a continuation of the tradition and political thought of Józef Piłsudski. First of all, the concept of "Mizhmorya" is closely related to his view of Poland's foreign policy in the interwar period. However, its origins go back to the beginning of the 20th century, when there were discussions about Poland's borders and its role in Europe after it gained independence. The main question concerned Poland's ability to effectively resist the expansion of neighboring states – Germany and Russia. The actualization of the "Mizhmorya" concept at the current stage and the transformation of the latter into the "Three Seas" initiative began after the Russian aggression in Ukraine in 2014. In its current version, the concept includes the southern and eastern vectors of integration. This is a qualitative change, since for many centuries Poland's foreign policy was formed on the East-West axis, paying much less attention to the North-South axis. It is worth noting that the concept of "Mizhmorya", which in its current version has turned into "Three Seas", is not considered as an alternative for membership in the EU and NATO. At the current stage, it does not have an independent character, complementing the generally pro-Western orientation of Poland and its other participants. In connection with the involvement of 12 countries in the "Three Seas Initiative" and the active role of Croatia, Romania and other states in it, it is losing connection with the original concept of the "Midsea". It is becoming a format of regional cooperation within the EU, but it has quite strong foundations. Its success also depends on external factors: West-Russia relations, US activity in Central and Eastern Europe, and the difficult-to-predict future of the European Union. One can debate for a long time about the functionality and competitiveness of the new association in relation to other numerous regional entities, but one thing remains important: the implementation of the "Three Seas" initiative will start the process of building the energy independence of the countries of the Eastern European region from Russia. At the summit on June 20, 2022, the countries of the "Three Seas" initiative granted Ukraine the special status of a participating partner of the association. It is worth noting that Ukraine's membership in "Trimory" is part of our country's path to membership in the European Union. The concept envisages the development of world trade through the creation of new European logistics corridors, therefore it is important for Ukraine to become one of the transitors along these routes. Several areas of Ukraine's cooperation with the participating countries of the "Three Seas" should be highlighted: the creation of the trans-European highway Via Carpathia, where Ukraine will play the role of an important logistics center; energy cooperation, Ukraine has one of the largest gas storages in the region and, using the capabilities of the Poland-Slovakia, Poland-Ukraine interconnectors, it is possible to meet the needs of all countries of the Three Seas; the export of Ukrainian electricity can help the countries of the "Three Seas" to become independent from the energy pressure of the Russian Federation; infrastructure and digitalization (countries should work on expanding checkpoints at the borders of Ukraine). Our state can support many infrastructure projects in the field of digitization and strengthen regional digital connections. So, the "Three Seas" initiative is Ukraine's perspective to take a place on the European market and completely abandon logistical ties with the occupying country.