Japan as a New Strategic Partner in the Three Seas Initiative: Opportunities and Challenges Ahead

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Introduction

by Sayuri Romei 

In April 2024, Japan joined the Three Seas Initiative (3SI) as a new strategic partner alongside the United States and the European Union. The 3SI was established in 2015 with the objective of strengthening connectivity and reducing the disparities in Central and Eastern Europe (CEE) and the Baltic states. The initiative promotes the development of infrastructure in the energy, transport, and digital sectors in the region surrounded by the Baltic Sea, the Black Sea, and the Adriatic Sea. The war in Ukraine has highlighted the relevance of this initiative and has underscored the frail infrastructure in the region and CEE’s economic dependence on Russia. As it becomes increasingly clear that the security and stability of the Euro-Atlantic and the Indo-Pacific regions are inseparable, Japan is compelled to serve as an active partner in the 3SI as its role is also closely connected to the quality of assistance and support to Ukraine.

As Japan embarks on this new partnership with CEE and Baltic countries, however, moving beyond the rhetoric about the importance of this initiative and taking concrete action is a challenge that all the countries involved will have to grapple with. Japan’s dialogue with CEE, and in particular with the Visegrad-4 (V4) group, i.e., Hungary, Poland, the Czech Republic, and Slovakia, officially started in the early 2000s. For the past twenty years, the relationship has mostly been smooth and without major problems. However, Japan’s engagement with those countries has lacked dynamism, as Japanese foreign policy has mainly been focused on the United States and China. Japan’s investments in CEE have been limited and cautious, and visits from high-ranking Japanese officials have been sporadic. In fact, the visits to Japan by the heads of the states of the V4 and CEE countries have always outnumbered those by their Japanese counterparts. Twenty years later, as CEE countries are realizing that the economic benefit from China is not as great as they had expected, Japan is in a good position to rekindle this relationship. In a January 2022 interview with Nikkei, Akio Miyajima, Ambassador of Japan to Poland, argued that it is crucial for Japan to strengthen relations with these countries. At the time of the interview, Russia had not yet invaded Ukraine, and the Ambassador lamented that Japan remained disinterested in the Ukraine issue. Since the invasion a month later, however, Japan has not only taken a clear stance in condemning Russia’s aggression, it has also taken a leadership role in investing in the reconstruction of Ukraine.

One of the main concerns about the 3SI is that it currently lacks cohesiveness, as the twelve participating nations are too divided to agree on major joint investments. Another issue is that the initiative mainly takes place on the political level, and cooperation on other levels and dimensions are presently non-existent. How can Japan, in coordination with the United States and Europe, contribute to creating a more systematic approach to non-political partnerships and effective financial support for the participating nations of the 3SI? The topic is still under-researched and as Japan’s strategic partnership was formalized just last year, now is an ideal time for experts from Japan, the United States, and the EU to identify opportunities and common challenges, and discuss ways to jointly implement a roadmap as strategic partners in the 3SI framework.

As 2025 marks the tenth anniversary of the establishment of the 3SI, it is critical for Japan and the other strategic partners to start contributing concretely to the initiative and to deepen their engagement with the participating nations. The tenth summit of the 3SI was held in Warsaw on April 28-29, 2025, and GMF Indo-Pacific partnered with the Embassy of Japan in Washington, DC, to publish this volume, which gathers the findings and perspectives of five authors from Japan, Europe, and the United States. Prof. Beata Bochorodycz of Adam Mickiewicz University and Dr. Bart Gaens of the Finnish Institute of International Affairs offer a European perspective on Japan’s potential role in the 3SI. Bochorodycz argues that Japan’s engagement will contribute greatly to regional infrastructure development while counterbalancing Russian and Chinese influences in the region. Gaens asserts that Japan’s interest in 3SI is multifold and covers several different areas: business and economics, development and connectivity, and geopolitics. However, he argues that there are also several challenges that impede Tokyo’s stronger involvement, and offers recommendations on its future engagement with the CEE countries. Anthony Kim of the Heritage Foundation and Mirna Galic, formerly with the United States Institute of Peace, contribute to this volume from American perspectives. Kim emphasizes the importance of the 3SI as a platform for attracting private sector investors and encourages Japan to go beyond its political partnership, while Galic reflects on how the 3SI may benefit Japan’s interests and analyzes concrete ways in which Tokyo can support the initiative. Finally, Ambassador Akio Miyajima, who served as Japanese Ambassador to Poland from 2020-2024, leans on his direct experience to recount the strategic evolution of Japan’s engagement with the CEE countries. He examines the Japanese government’s perspective from its first concerns about the expansion of Chinese influence in Europe to the major strategic recalibration that followed Russia’s invasion of Ukraine in February 2022. Ambassador Miyajima concludes by analyzing the current global uncertainty stemming from the second Trump administration and offers recommendations on ways to strengthen Japan’s position as a strategic partner to the 3SI.