The challenge for Australia and Japan, 50 years since the Basic Treaty of Friendship and Co-operation was first signed, is the need to translate strategic alignment into durable capability and coordinated action. Japanese Prime Minister Sanae Takaichi is expected to visit Australia in 2026 to commemorate the 50th anniversary of the treaty. That anniversary offers more than a diplomatic milestone; it provides a moment to re-anchor the relationship in the realities of today’s strategic environment, not the assumptions of past eras.
The Australia–Japan relationship, long grounded in shared democratic values and economic interdependence, has deepened markedly as China has become more assertive across the region. Cooperation has expanded from diplomacy and trade into defence and security in ways that would have been politically difficult only a decade ago.
In mid-2025, Japan participated for the first time in an AUKUS-related exercise involving uncrewed underwater vehicles in Jervis Bay. Soon after, Australia selected Japan’s Mogami-class design for its future frigate program, some of which will be built in Western Australia. This engagement reflects growing trust, greater interoperability and a shared assessment of regional risk, particularly around Beijing’s attempts the change the status quo by force.
That assessment is backed by experience. Japan continues to face persistent pressure around the Senkaku Islands, with regular incursions by China Coast Guard vessels or helicopters into waters and airspace claimed by Japan. Chinese military and paramilitary activity in the vicinity—including close approaches to Japan’s territory and air and maritime operations—has become a routine feature of Japan’s security environment. These actions are calibrated to remain below the threshold of armed conflict, but they impose constant strategic and political pressure.
Australia is encountering similar patterns closer to home. In 2025, unsafe intercepts involving Chinese military aircraft and Australian patrol planes, live-fire naval drills conducted unusually close to Australia’s eastern seaboard, and the movement of Chinese state-linked vessels through sensitive maritime areas all reinforced Canberra’s assessment that strategic competition is increasingly playing out in Australia’s immediate neighbourhood.
In November, Takaichi signalled a major shift in Tokyo’s defence posture when she said that a Chinese attack on Taiwan would also threaten Japan’s survival. China reacted strongly to this statement, including by increasing trade suspensions and military provocations. Beijing also responded through less direct methods, such as cancelling Japanese artists’ performances and spreading disinformation around Ryukyuan—now Okinawan—history.
Together, these activities reflect a broader pattern of hybrid or grey-zone pressure: actions designed to intimidate, test resolve and normalise risk without triggering outright conflict. They are not isolated incidents, but rather part of a sustained effort to reshape the strategic environment to China’s advantage.
Australia’s and Japan’s responses to these pressures have increasingly converged. Both governments have been more willing to call out unsafe or coercive behaviour publicly, and both have emphasised the importance of international law and freedom of navigation. When incidents have occurred, leaders and defence ministers have coordinated their messaging, reinforcing the signal that pressure on one will not be treated in isolation.
This alignment creates opportunities and responsibilities. While Australia and Japan are not formal allies, they now operate as close strategic partners. This relationship is enabled by a bilateral reciprocal access agreement, joint exercises and growing defence industrial cooperation.
As members of the Quad, which also includes the United States and India, they also share an interest in ensuring that the group remains a practical mechanism for regional stability rather than a rhetorical one.
That will not be straightforward. The Quad’s effectiveness depends not only on Australia and Japan, but also on how well the US and India can align their priorities in moments of stress. Both Tokyo and Canberra are likely to find themselves increasingly acting as stabilisers: encouraging coordination, managing differences and reinforcing the value of rules and restraint when larger powers diverge.
Uncertainty around US behaviour reinforces the need for middle powers such as Australia and Japan to invest in their own partnerships and regional networks, rather than relying solely on assumptions of great-power consistency.
Looking ahead, Australia and Japan are well-placed to leverage their complementary strengths. Both have credibility in Southeast Asia and the Pacific, strong relationships with the Association of Southeast Asian Nations, and a shared interest in working through regional institutions such as the Pacific Islands Forum and the Indian Ocean Rim Association. Both are also grappling with similar challenges: economic security, supply-chain resilience, trusted technology, maritime security and the protection of an open trading system.
Declarations alone will not sustain a free, open and rules-based Indo-Pacific order. Rather, it will depend on partnerships that are prepared to absorb pressure, coordinate responses and invest in long-term resilience. On that test, the Australia–Japan relationship is increasingly indispensable.
