Discussions on Mogami-class Frigate Export Drive Japan-Australia-Indonesia Cooperation; First Defense Minister Meeting a Litmus Test for Southern SLOC Defense

On the 26th, defense ministers from Tokyo, Canberra, and Jakarta connected via telephone for their first simultaneous trilateral discussions. On the surface, the focus was on "contributing to peace and stability in the region and the world." However, from the perspective of a former Japan Maritime Self-Defense Force (JMSDF) officer, what truly deserves attention is not the format of the talks but the specifics of the naval cooperation moving behind the scenes. A new ship proposal based on the Mogami-class frigate is being considered for Australia, while discussions on exporting JMSDF vessels are progressing for Indonesia. The trilateral cooperation has begun to address the question of who will practically support the maritime routes from the South China Sea to the Lombok Strait and the Malacca Strait.

What Was Confirmed in the First Trilateral Meeting

According to Japan's Ministry of Defense, the three countries confirmed the importance of close communication and shared the intention to cooperate in contributing jointly to peace and stability in the region and the world.

The wording of the joint announcement itself is cautious. However, the timing is not coincidental. Australia and Indonesia signed the Jakarta Treaty in February this year, strengthening the institutional foundation for defense cooperation. Furthermore, Indonesia agreed to expand military cooperation with China on August 21, making it natural to view Tokyo and Canberra as seeking a balance that prevents Jakarta from leaning too far toward one side. For Japan, this is a strategic move to support the defense of sea lanes extending south from the Nansei Islands through not only alliances but also quasi-allied multilateral cooperation.

The Significance of the Mogami-class Frigate

At the center of the equipment cooperation is the naval vessels. The Mogami-class based proposal being considered for Australia features a compact hull of approximately 3,900 tons, designed to incorporate various sensors and multi-mission capabilities, with advancements in automation. While further scrutiny is needed to determine how well it meets the Australian Navy's requirements for numerous maintenance and long-term operation, it is one of the few cases where Japan can market not just a finished product but an operational concept. The discussions for Indonesia also hold significance as a platform for sharing patrol, surface surveillance, and strait navigation management, rather than being merely a business negotiation.

• The Mogami-class based proposal has a standard displacement of approximately 3,900 tons, emphasizing stealth and automation.
• The Australian project has the potential to develop into industrial cooperation, including joint development and local construction.
• The Indonesian project will hinge on whether it can expand to include operational, maintenance, and educational support.

Interests of the Three Countries in Southern SLOC Defense

Much of Japan's energy and materials pass through the South China Sea and the straits around Indonesia. If pressure from the Chinese Coast Guard and Navy becomes normalized here, the issue for Tokyo will not be limited to the prelude to a Taiwan contingency but will also become a vulnerability in commercial shipping during peacetime. Australia is irreplaceable as a rear supply and maintenance base, while Indonesia is crucial as a geographical chokepoint for strait management. If the trilateral discussions are institutionalized, there is significant room to advance to joint training, common communication procedures, and supply agreements. In the author's view, the value of Japan-Australia-Indonesia cooperation lies not in forming a new military bloc but in dispersing maritime situational awareness during peacetime and buying time for decision-making during crises.

The Remaining Risk is the Speed of Politics

That said, it is premature to overestimate trilateral cooperation. Indonesia does not intend to completely sever ties with China, and Australia also has economic dependencies on China. Japan's defense equipment transfers have often lacked finalization in terms of price, construction schedules, and local industry participation. The effectiveness of this framework will be judged by whether the telephone talks become regularized and whether naval projects connect to training plans and information sharing. The true challenge lies not in the performance specifications of the ships but in how quickly the three countries can see the same picture in the gray areas before a crisis.