Croatia called for a stronger financial framework to underpin the Three Seas Initiative (3SI) on April 28 and 29, as regional leaders and investors gathered in Dubrovnik to boost infrastructure, energy and digital investment across Central and Eastern Europe.

The 3SI brings together 13 European Union member states between the Baltic, Black and Adriatic seas. Launched a decade ago by Croatia and Poland, it has increasingly focused on closing infrastructure gaps between Western Europe and the new EU members.

Prime Minister Andrej Plenković, hosting the summit and accompanying business forum, said the next phase of the initiative would depend on scaling up funding mechanisms and mobilising private capital.

“In the next ten years, we need to focus more on finance and investments through various models and the support of financial institutions so that this Initiative becomes a sustainable organisation that will be a driving force in the future,” Plenković said, according to a government statement.

More than 1,600 business leaders attended the Dubrovnik forum, reflecting investor interest in a region seen as one of Europe’s fastest-growing. Plenković said the turnout signalled “a clear signal that investors see the countries of Central and Eastern Europe as an engine of economic development for the entire continent.”

The Three Seas’ region is one of the fastest-growing worldwide, Polish President Karol Nawrocki told the conference. “It is a market that generates a total of €2 trillion annually, which accounts for nearly 20% of the European Union’s GDP. Together – all 13 countries – we form the world’s seventh largest economy,” he said during a joint press conference with Plenković and Slovak President Peter Pellegrini.

A key focus of Croatia’s presidency has been strengthening financial instruments to support cross-border projects. On April 28, financial institutions signed a Fund of Funds agreement under the European Investment Bank (EIB), aimed at channelling capital into priority sectors including transport, energy and digital infrastructure.

Plenković said the initiative should also secure a stronger role in the European Union’s next multi-year budget, arguing that cross-border projects in the region require dedicated funding streams.

“All of this is an opportunity to be even better and to improve critical infrastructure in terms of transport and energy, but also in terms of digital transformation,” he said.

The initiative has gained backing from international partners including the United States, Japan and, newly, Italy as a strategic partner, reflecting its growing geopolitical and economic relevance.

Alongside institutional financing from bodies such as the EIB, World Bank and European Bank for Reconstruction and Development, Plenković outlined private investment as a key pillar. “As the third way of financing,” he said, the initiative should rely on “investments of private companies, banks, funds – all those who are interested in investments, profits and new jobs.”

Energy connectivity featured prominently at the summit, with Croatia positioning itself as a regional hub. Plenković signed a Southern Interconnection Agreement with Bosnia & Herzegovina to link it to Croatia’s LNG terminal on the island of Krk.

He described the project as strategic for regional energy security and growth, saying it would “end dependence on Russian fossil fuels and enable further economic growth” in Bosnia.

“With goodwill and strong investments in domestic energy infrastructure, we will continue the policy of sustainable growth of our GDP, high employment and falling unemployment,” Plenković added.

In the north, Narowiki said Poland is ready to become the gateway for US gas to the region, pointing to the Baltic Sea terminal in Świnoujście and investments in a floating terminal in the Baltic.

Plenković said the initiative’s core achievement had been to highlight disparities in development and push for equal access to investment. “This initiative sends a message that countries that have not had the opportunity to develop in the same way want the same treatment when it comes to infrastructure, energy, digital transformation and transport,” he said.

Leaders also stressed the importance of north-south connectivity in a shifting geopolitical environment marked by war in Ukraine and energy market volatility.

“The goal is to connect the Baltic, Black and Adriatic Seas, to strive to improve our connectivity – both in infrastructure, transport and energy – and to give a common impetus to further processes of digital transformation,” Plenković said.

With global uncertainty driving demand for resilient supply chains and energy diversification, officials said the initiative could play a larger role in shaping Europe’s economic architecture, provided it secures sufficient and sustained investment.