The Central European Initiative (CEI) and the Tree Seas Initiative (TSI) are different concepts of cooperation in Central and Eastern Europe. While the CEI is the largest and oldest regional group in this part of Europe, the TSI was established in 2016. Despite differences, common features of both initiatives can be distinguished: they both include the same nine countries, none of them includes Germany and Russia and none of them has a strong financial base and clearly defined goals. In formal terms, these are not international organizations sensu stricto, having their statutes, defining their goals, structures and bodies, etc. Currently, after more than fifteen years of its functioning, the CEI is in a phase of stagnation and its rank weakens. Italy is too weak to effectively lead the group and give it certain dynamics. The informal leader of the TSI is Poland, which is not able to ensure the success of this initiative without external support. Further interest of the United States in the TSI will have a decisive impact on the development of this group.
