On September 5, 2025, at the bustling naval base in Yokosuka, Japan, a momentous scene unfolded: Australian Defense Minister Richard Marles, flanked by Japanese Defense Minister Gen Nakatani, stepped aboard the JS Mikuma, a sleek Mogami-class frigate. The visit marked far more than a diplomatic courtesy—it was a symbolic handshake sealing a new era of military cooperation between Australia and Japan, two nations determined to navigate the choppy waters of Indo-Pacific security together.
This high-profile tour came just a month after Australia announced it would replace its aging ANZAC-class warships with 11 state-of-the-art Mogami-class frigates, all produced by Mitsubishi Heavy Industries. For Japan, the deal is a shot in the arm for its defense industry, which has sought to expand its international footprint since losing out on Australia’s submarine contract to France in 2016. As reported by the Associated Press, the contract—valued at approximately US$6 billion—represents one of Japan’s largest defense export deals since World War II.
According to Kyodo News, Marles was unequivocal about the reasoning behind the decision: "It's really important that we are getting new warships operating in our navy as soon as possible," he said, emphasizing the urgency posed by a "severe security environment" in the Indo-Pacific. Marles, who also serves as Australia’s deputy prime minister, insisted that the choice was "entirely based on capability," describing the Mogami-class as "the most cost-effective capability" for Australia, as it requires fewer crew members than the current fleet. The first three vessels are likely to be built in Japan, with the remainder potentially constructed in Perth, Western Australia—part of Australia’s ambition to establish a continuous naval shipbuilding capacity at home, with Mitsubishi as a key partner.
But the significance of the deal stretches well beyond hardware. Both countries have made it clear that this is about strategic alignment in an increasingly uncertain region. As Marles told Kyodo News, "There is no country with whom we have greater strategic alignment today than Japan." He expressed hope that, as the two nations approach the 50th anniversary of their bilateral treaty next year, their "special strategic partnership" would be taken to the next level. "We are transforming our relationship, and we are taking it to the next level," he declared.
The timing of the announcement is no accident. Just days earlier, Beijing hosted a massive military parade attended by Russian President Vladimir Putin and North Korean leader Kim Jong Un—a not-so-subtle display of shifting alliances and power plays in the region. According to Channel NewsAsia, Japanese and Australian ministers met in Tokyo shortly after the parade, agreeing to deepen defense ties and reaffirming the importance of working together to "prevent unilateral changes to the status quo by force." Japanese Defense Minister Gen Nakatani told journalists, "Reaffirming the importance of working together to prevent unilateral changes to the status quo by force, we agreed to strengthen cooperation." He also highlighted plans to enhance collaboration with regional partners, including the Philippines, India, South Korea, ASEAN, and Pacific countries.
Australia is not acting in isolation. Its military is undergoing a sweeping restructure, focused on bolstering its navy with long-range firepower—an unmistakable signal to China, whose assertive activities in the East and South China seas have rattled nerves across the region. As Japan’s public broadcaster NHK reported, both countries expressed concerns over destabilizing activities in these contested waters and reaffirmed their opposition to any unilateral changes to the status quo. Australian Foreign Minister Penny Wong echoed this sentiment, saying, "We've also expressed concerns over destabilising activities in the East and South China seas and reaffirmed our long-standing position to oppose any unilateral changes to the status quo." She added, "We need to work together to build resilience and respond to emerging threats."
The alliance is not just about ships and drills. On the same day as the Yokosuka visit, the defense and foreign ministers of both nations pledged to expand joint military exercises and deepen cooperation in energy and critical minerals—a nod to the economic dimension of security. In a separate meeting, Japanese Foreign Minister Takeshi Iwaya and Australian Foreign Minister Penny Wong inked an agreement aimed at strengthening their coordination for evacuating nationals overseas in emergencies. This practical step underscores the growing trust and operational integration between the two countries.
Japan, for its part, has been accelerating its own military buildup and looking to diversify its defense partnerships beyond its traditional alliance with the United States. Nakatani described Australia as a "semi-ally," and the two countries have benefited from a reciprocal access agreement implemented in 2023, which enables faster troop deployment and facilitates joint drills and disaster relief operations. The Japanese government has also thrown its weight behind the Mogami-class frigate project, teaming up with Mitsubishi and other manufacturers to ensure the program’s success.
For Australia, the decision to go with the Mogami-class frigate is as much about future-proofing its navy as it is about geopolitics. Marles explained to Kyodo News that the new vessels are not only more capable but also require fewer crew members—an important consideration as navies worldwide grapple with recruitment and retention challenges. The plan calls for the contract to be finalized by early 2026, with delivery of the first ships by 2029. If all goes according to plan, Australia’s navy will be equipped to face the challenges of a region where, as Marles put it, the "rules-based order is under strain."
The deal’s ripple effects extend to supply chains and economic security. Nakatani emphasized that the agreement "strengthens supply chain cooperation between the two countries and contributes to the peace and stability of the Indo-Pacific region." The hope is that such cooperation will help insulate both nations from disruptions, whether they arise from geopolitical tensions or other shocks.
Analysts see the deepening Australia-Japan partnership as part of a broader realignment in the Indo-Pacific. With the United States’ role in the region evolving and China’s ambitions growing ever more apparent, middle powers like Japan and Australia are finding common cause. Their collaboration—whether on the deck of a warship or in the negotiating room—signals a determination to shape their own destiny, rather than be shaped by the designs of others.
The Yokosuka meeting, then, was not just about a tour of a gleaming new frigate. It was a declaration of intent: that Australia and Japan, facing a world in flux, are prepared to stand together, invest in each other, and chart a course for security and stability in the Indo-Pacific. The next few years will test the strength of this partnership, but if the events of September 5 are any indication, both countries are ready for the journey ahead.