Japan And Australia Deepen Defence Cooperation – Analysis
China’s belligerent behaviour in the Indo-Pacific region has led smaller countries in the Indo-Pacific region with similar concerns to indulge in hedging strategies with a view to check China. Amid shared concerns about Chinese military activities in the region, Japan’s Defence Minister Shinjiro Koizumi launched a “framework for strategic defense coordination” during the visit to Tokyo by Australia’s Defence Minister Richard Marles in the first week of December 2025.
This move comes after ties between Tokyo and Beijing dipped to their lowest point in over a decade following Japanese Prime Minister Sanae Takaichi’s remarks in the Diet on 7 November 2025 hinting that a Chinese blockade in the vicinity of Taiwan could be a “survival-threatening situation” for Japan, potentially triggering the mobilisation of the Japanese Self-Defence Forces (SDF). This evoked sharp reaction from China and ties between the two countries suddenly nosedived.
So, what does the new security framework between Japan and Australia mean? Since this will include a comprehensive annual meeting between representatives of the quasi-allies’ defence ministries, militaries and intelligence communities, future defence collaboration would be conducted to ensure the two sides work together more effectively and with greater strategic alignment “at all levels and in all situations”. Thus the framework would cover “all areas”, including cyber, space, logistics and supply-chain management as some of the intended fields of collaboration.
It transpired that the Australian government decided to engage with the new government in Japan headed by Takaichi by rushing its Defence Minister Marles to Tokyo and work together in responding to increasingly complex global challenges. Marles underlined that Australia’s relationship with Japan continues to grow from strength to strength, underpinned by close strategic alignment, mutual ambition and enormous potential. As mentioned, Takaichi’s remarks that a hypothetical Chinese attack on democratically governed Taiwan could trigger a military response from Tokyo had infuriated Beijing.
There are clear indications that Japan-Australia defence partnership is deepening in recent times, also with a commercial overtones. For example, Australia awarded a A$10 billion ($6.5 billion) contract to Japanese company Mitsubishi Heavy Industries in August 2025 to build warships for Australia, marking Tokyo’s most consequential defence sale since ending a military export ban in 2014 as it steps away from post-war pacifism.
Australia plans to deploy the Mogami-class frigates to defend critical maritime trade routes and its northern approaches in the Indian and Pacific Oceans, where China’s military footprint is expanding. Australia is also reaching out with the US and Britain.
After visiting Tokyo, Marles visited the US and Britain within days wherein the defence ministers of the three countries reaffirmed to their shared commitment to the AUKUS trilateral security partnership. In a joint statement, the three defence ministers – Pete Hegseth of the US, Marles of Australia and John Healey of the UK – in their annual AUKUS defence ministers’ meeting, shared their intent to move “full steam ahead” on delivering priority infrastructure and workforce shift in support of an enhanced trilateral industrial base.
While in Japan, Marles toured a Japanese navy frigate of the same Japanese-made model that Australia has chosen for its new fleet, in a clear demonstration of intent that both are determined to deter growing Chinese influence. The former Defence Minister of Japan Gen Nakatani during the Ishiba government had hosted Marles aboard the MSDF’s Mikuma, a month after Australia chose Mogami-class frigates produced by Mitsubishi Heavy Industries to replace Australia’s aging fleet of ANZAC-class warships. The deal that time gave a major boost of confidence to Japan’s still-underdeveloped defence industry after it lost out on Australia’s submarine contract to a French company in 2016. That time, the two ministers agreed to conclude the procurement contract as quickly as possible. For Australia, the selection of the Mogami-class frigate as the general-purpose frigate for the Royal Australian Navy is genuinely a milestone moment in the bilateral relationship between Japan and Australia.
Viewed from Japan’s perspective, it has been accelerating its military build-up by expanding ties beyond its only treaty ally, the US, and now considers Australia to be a semi-ally. The frigate deal thus strengthens supply chain cooperation between the two countries and contributes to the peace and stability of the Indo-Pacific region. Earlier in September 2025, the defence ministers of Japan (during Ishiba government) and Australia, Takeshi Iwaya and Perry Wong held security talks in which they pledged to expand joint military exercises and cooperation in energy and critical minerals. They reiterated the importance of cooperating with the US and raised concern over China’s assertive activities. Both signed an agreement aimed at strengthening their coordination in the evacuation of their nationals from overseas in case of emergencies.
The September 2025 meeting of Foreign and Defence Ministerial Consultations, known as 2+2, was a landmark agreement to jointly develop new warships for the Australian Navy and this intent meant to deepen security cooperation to counter China’s growing military presence in the Indo-Pacific region. This was the 12th time the 2+2 was held, represented by Japan’s Foreign Minister Takeshi Iwaya and Defence Minister Gen Naktani, and counterparts from Australia Penny Wong and Richard Marles.
Thus it transpires that Japan is committed to strengthen its security cooperation with Australia to cope with increasing military activities of China in East and South China Seas. That is why Japan chose a proposal to jointly develop vessel with Australia, which is based on an upgraded version of the Mogami-class frigate from Mitsubishi Heavy Industries Ltd. Australia chose the Japanese company in a competing bid from German rival, a significant milestone as it is the largest-ever joint project between the defense industries of Japan and Australia. There is also an agreement between the two sides for Australian destroyers using the MSDF base in Yokosuka for resupply and maintenance and the Air SDF participating in the Royal Australian Air Force’s drone testing. Both also agreed to in a MoU to cooperating on evacuating their citizens from other countries during emergencies, such as conflicts or disasters. This was the second such agreement for Japan, following a similar one inked with South Korea. These developments are significant as the US under Trump’s presidency putting primacy on “America First” policy, implying an inward-looking outlook, and therefore Japan and Australia as two important allies of the US are carving their own policies together and strengthening bilateral relationship with aim to keep China in check.