Three Seas Initiative

The Three Seas Initiative (3SI or TSI), known also as the Baltic, Adriatic, Black Sea (BABS) Initiative or simply as the Three Seas (Latin: Trimarium, Polish: Trójmorze), is a forum of 13 states in the European Union, and 4 non-EU partner-participants, roughly connecting the Baltic, Adriatic, and Black Seas in Central and Eastern Europe. The Initiative aims to create a regional dialogue on questions affecting the member states.

In 2016, representatives of the original 12 member states (Austria, Bulgaria, Croatia, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania, Slovakia, and Slovenia) met for their first summit in Dubrovnik, Croatia. At the seventh summit in 2022, Ukraine received the status of a partner-participant. At the 2023 summit, Greece became a member, and Moldova a partner-participant. At the 2025 summit, Albania and Montenegro became partner-participants.

The twelve Three Seas countries cover 29 per cent of the European Union's territory (1,210,000 km² or 470,000 sq mi), are home to 25 percent of the European Union's inhabitants (110 million), and produce €2.3 trillion or one seventh of the EU's GDP (nominal).

The Three Seas Initiative, which was influenced by the Polish interwar Intermarium concept, was launched in 2015 by Polish President Andrzej Duda and Croatian President Kolinda Grabar-Kitarović.

The Initiative's first summit, held in Dubrovnik, Croatia, on 25–26 August 2016, ended with a declaration of economic cooperation in energy and in transport and communications infrastructures. Polish President Andrzej Duda called the initiative "a new concept to promote Europe's unity and cohesion... an idea of cooperation among 12 countries located between the Adriatic, Baltic and Black Seas, the three seas of Central Europe."

Guests included Chinese Ministerial Assistant for Foreign Affairs Liu Haixing, who spoke about Three Seas Initiative's interconnectedness with China's Belt and Road Initiative, and former US National Security Advisor General James L. Jones, who stressed the Three Seas Initiative's role in European development and security.

The Initiative's second summit was held 6–7 July 2017 in Warsaw, Poland. Guest attendees included US President Donald Trump. The participating countries unanimously agreed to set up a Three Seas Business Forum.

The Initiative's third summit took place 17–18 September 2018 in Bucharest, Romania. Participants approved interconnection projects in three key areas: transport, energy, and digital. Guest attendees included President of the European Commission Jean-Claude Juncker, German Foreign Minister Heiko Maas, and US Secretary of Energy Rick Perry. The first edition^{[clarification needed]} of the Business Forum was organised. A 3SI Network of Chambers of Commerce was created, and a letter of intent was signed concerning establishment of a Three Seas Investment Fund.