The following is the March 19, 2025, is the Congressional Research Service In Focus report: The Three Seas Initiative.
From the report
The Three Seas Initiative (3SI) is a regional effort in Europe to expand cross-border energy, transportation, and digital infrastructure and boost economic development in the area between the Adriatic Sea, Baltic Sea, and Black Sea. Thirteen countries (Austria, Bulgaria, Croatia, the Czech Republic, Estonia, Greece, Hungary, Latvia, Lithuania, Poland, Romania, Slovakia, and Slovenia) participate in the 3SI. All 3SI countries are European Union (EU) members, and all but Austria are NATO allies. Moldova and Ukraine, which are candidates for EU membership, are associated participating countries.
The United States, along with Germany, Japan, and the European Commission (the EU’s executive), has been a 3SI strategic partner. During the first Trump Administration and the Biden Administration, U.S. officials expressed diplomatic support for the 3SI, and senior U.S. officials (including President Trump in 2017) joined its annual summits. The United States has provided financing through the U.S. International Development Finance Corporation (DFC) for the Three Seas Initiative Investment Fund (3SIIF) to support projects that seek to improve energy security, energy supply diversification, and connectivity.
Congress has considered some legislation expressing support for the 3SI. For example, in the 118th Congress, a Senate-passed version (S. 2226) of the National Defense Authorization Act for FY2024 (NDAA) included provisions supporting the 3SI; the enacted version of the FY2024 NDAA (P.L. 118-31) did not include these provisions. Proposed legislation (H.R. 3344) that passed the House of Representatives in the 117th Congress would have conveyed support for the 3SI “to increase infrastructure resiliency and reduce reliance on malign actors, including in the telecommunication space.” In 2020, during the 116th Congress, the House adopted a resolution “expressing support of the Three Seas Initiative in its efforts to increase energy independence and infrastructure connectivity thereby strengthening the United States and European national security” (H.Res. 672).
Initiative Overview
The 2025 3SI Summit, scheduled for April 28-29, 2025, in Warsaw, Poland, marks the 10th anniversary of the initiative and is expected to set the direction of the 3SI for the next decade. The 3SI was launched in 2015 by the presidents of Croatia and Poland, and summits have been held annually since 2016.
An overarching goal of the 3SI is to develop a north-south infrastructure corridor in the region. In part as a legacy of the Soviet Union’s Cold War-era dominance over most of the region, east-west infrastructure remains considerably more developed than north-south linkages. Particularly with regard to energy security, the dominance of east-west pipelines and limited alternatives to them have constrained past European efforts to end energy dependence on Russia. Many observers have described the expansion of energy infrastructure, including liquefied natural gas (LNG) terminals, as key to opening up new routes for energy supplies to Europe. Road and railway networks in the 3SI region also are generally less developed and less efficient than in other parts of the EU.
3SI members assess that Russia’s full-scale invasion of Ukraine starting in 2022 has made development of resilient, integrated regional infrastructure more imperative. Some supporters also describe the 3SI as a potential counterbalance to the People’s Republic of China’s (PRC’s) involvement in regional projects as part of its Belt and Road Initiative.
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