OCEAN and the Making of a Networked Indo-Pacific

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Japan’s Minister of Defence, Gen Nakatani, introduced the concept of OCEAN (One Cooperative Effort Among Nations) at the 22nd Shangri-La Dialogue in Singapore in May 2025. The proposal frames the Indian and Pacific Oceans as a single strategic continuum, highlighting the imperative of like-minded states to engage in comprehensive security cooperation for the preservation of a rules-based order. According to Nakatani, OCEAN is not merely a slogan but a strategic framework designed to reinforce cooperation among countries that share values such as transparency, openness, accountability, and respect for international law.

The core of OCEAN lies in promoting collaboration across multiple domains of security. It extends beyond traditional military ties to encompass cooperation in logistics, defence technology and equipment, disaster relief, maritime security, and information sharing. This reflects Tokyo’s recognition that Indo-Pacific security challenges are becoming increasingly complex and multifaceted, ranging from illegal maritime activities and coercive behaviour at sea to humanitarian crises triggered by climate change and natural disasters. Through OCEAN, Japan positions itself as a convener of multilateral security cooperation, while complementing existing frameworks such as the US–Japan alliance, the Quad, and ASEAN-led mechanisms.

A strategic framework designed to reinforce cooperation among countries that share values such as transparency, openness, accountability, and respect for international law.

Engagement with ASEAN partners forms a central component of OCEAN. Nakatani stressed that the concept is not intended to replace but rather strengthen existing regional frameworks, particularly through ASEAN-led mechanisms and initiatives such as the Vientiane Vision 2.0 and JASMINE (Japan–ASEAN Ministerial Initiative for Enhanced Defence Cooperation). Japan has also backed OCEAN with practical steps. In September 2025, during bilateral talks in Manila, Japan and the Philippines discussed OCEAN as a shared framework for deepening defence equipment cooperation and enhancing maritime domain awareness. Similarly, in Seoul, Nakatani emphasised OCEAN’s value for promoting multilateral cooperation among the US, South Korea, Australia, the Philippines, and Japan, thereby embedding the concept into wider regional dialogues.

Strategically, OCEAN represents an evolution of Japan’s security role in the Indo-Pacific, highlighting collective deterrence and capacity building. This reflects broader concerns in Tokyo's strategic thinking about the erosion of international norms, increasing maritime assertiveness, and coercive attempts to alter the status quo. Nakatani explicitly tabled OCEAN as a response to these challenges, urging countries in the region to bolster deterrence capabilities against unilateral actions to ensure that international law prevails in contested spaces.

Strategically, OCEAN represents an evolution of Japan’s security role in the Indo-Pacific, highlighting collective deterrence and capacity building.

In many ways, OCEAN represents an evolution of the strategic ideas first articulated by former Prime Minister Shinzo Abe in his “Confluence of the Two Seas” speech in 2007. It translates the “confluence” from an aspirational concept about shared geography and values into an actionable framework for joint security and capability-building in a contested Indo-Pacific. Abe’s concept laid the intellectual foundation for what later became the Free and Open Indo-Pacific (FOIP), which articulated Japan’s vision of linking the Pacific and Indian Oceans as a single strategic continuum shaped by shared democratic values and maritime commons. Nakatani’s OCEAN retains this maritime-centric worldview but strengthens the defence dimension by explicitly embedding military and defence-industrial cooperation within multilateral structures. Earlier policies, especially “Proactive Contribution to Peace” (2013) under Prime Minister Abe, already emphasised that Japan should play a more active role in regional and global security, primarily through capacity-building, defence cooperation, and adherence to international law. OCEAN builds on this logic by situating Japan as a facilitator of multilateral security. Rather than a purely national doctrine, it explicitly calls for collective frameworks anchored in shared values.

Where OCEAN differs from previous frameworks is in its conceptual positioning as a cooperative defence initiative. For instance, FOIP was primarily a broad diplomatic strategy, open-ended in membership and oriented as much toward values and development as security. OCEAN, by contrast, is more narrowly a defence cooperation framework that stresses logistics, interoperability, defence equipment transfer, and joint capacity building. This represents a sharper institutionalisation of Japan’s defence diplomacy, particularly with ASEAN partners.

Another departure is its focus on inclusivity through shared values but exclusivity in practice. While FOIP placed itself as “inclusive,” even allowing space for China if it respected international norms, OCEAN’s language makes clearer distinctions between those who uphold a rules-based order and those who undermine it. In this sense, it resembles the Quad’s orientation while being framed under Tokyo's leadership and with firm support for ASEAN centrality.

Finally, OCEAN also signals a shift in Japan's regional security role. Earlier doctrines (like “Proactive Contribution to Peace”) often relied heavily on the US–Japan alliance as the backbone of regional security. OCEAN, however, is Japan’s attempt to articulate an autonomous security vision that can tie together the US, ASEAN, Australia, South Korea, and potentially India under a cooperative framework—without always foregrounding Washington as the anchor. This reflects Tokyo’s growing confidence in shaping security architecture on its own terms.

In many ways, OCEAN represents an evolution of the strategic ideas first articulated by former Prime Minister Shinzo Abe in his “Confluence of the Two Seas” speech in 2007. It translates the “confluence” from an aspirational concept about shared geography and values into an actionable framework for joint security and capability-building in a contested Indo-Pacific.

However, OCEAN faces significant challenges. Existing capacity asymmetries between Japan and countries in Southeast Asia could limit meaningful participation unless Tokyo continues to offer sustained investment in training, technology, and resources. Moreover, Japan’s domestic legal and political constraints, rooted in its pacifist constitution and arms export rules, pose limits on the extent of defence equipment cooperation. There is also the risk that OCEAN could be perceived as duplicating or competing with other frameworks, such as AUKUS or the Quad, creating coordination dilemmas.

Currently, OCEAN is best understood as a normative and practical extension of Japan’s proactive security posture in the Indo-Pacific. It reinforces Japan’s role as a facilitator of multilateral defence cooperation, situating maritime and regional stability as collective responsibilities. The success of OCEAN will depend on its ability to remain inclusive, provide tangible benefits to partners, and avoid being perceived as overtly antagonistic. Nonetheless, as a strategic concept, OCEAN illustrates Tokyo’s intent to shape the regional security architecture at a time of intensifying great-power competition and increasing threats to the rules-based maritime order.

Pratnashree Basu is an Associate Fellow at the Observer Research Foundation.

• International Affairs
• Maritime Security
• India
• East Asia
• Free and Open Indo-Pacific (FOIP)
• Indo-Pacific security cooperation
• Japan ASEAN maritime cooperation
• Japan defence diplomacy
• Japan maritime security policy
• Japan OCEAN concept
• Japan Quad regional cooperation
• Multilateral defence cooperation in Asia
• OCEAN defence framework

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