Australia Orders 3 Upgraded Mogami Frigates in Japan’s Largest Defense Export Deal.

Australia has locked in the acquisition of three new general-purpose frigates, accelerating the overhaul of its surface fleet and strengthening its maritime combat power. The move directly boosts naval readiness and deterrence in the Indo-Pacific as aging Anzac-class ships approach retirement.

The Mitsubishi Heavy Industries-built ships are based on the advanced Mogami-class design, offering improved stealth, automation, and multi-mission capability. This combination enhances Australia’s ability to conduct anti-submarine warfare, surface combat, and regional force projection as modern naval competition intensifies.

Related Topic: Japanese Mogami-Class Frigates Explained as Selected by Australia for Its Naval Forces

Australian and Japanese defence ministers formalize the agreement in Melbourne for the delivery of the first three Mogami-class frigates (Picture source: Japan MoD)

This program is part of Project Sea 3000, initially structured as an open competition between several international shipbuilders to select a future general-purpose frigate. Following the selection of Mitsubishi Heavy Industries as the preferred contractor and the subsequent contract signature, the project is now centered on an upgraded Mogami-derived design, which is intended to form the basis of the eleven ships planned. The first three units will be built in Japan to meet delivery timelines, after which production is expected to transition to the Henderson shipyard in Western Australia, in line with national objectives for continuous naval shipbuilding and industrial development.

The Australian Department of Defence stated in a release issued on April 18, 2026, that Mitsubishi Heavy Industries was selected over Germany’s Thyssenkrupp Marine Systems based on a balance of cost, capability, and delivery schedule. The total program value is estimated between 15 and 20 billion Australian dollars over the coming decade, reflecting a broader effort to expand and renew the navy’s surface fleet.

The Mogami-class frigate features a design focused on reduced observability and multi-mission flexibility. With a displacement of approximately 5,500 tons at full load and a length of around 133 meters, the ship incorporates sloped surfaces and an integrated mast that encloses sensors and communication systems, reducing radar, infrared, and acoustic signatures. This configuration is intended to delay detection in contested environments, particularly against modern electronically scanned radars.

Its armament combines offensive and defensive systems suited to a range of missions. The main gun is a 127 mm Mk 45 Mod 4 naval gun capable of firing extended-range guided munitions. For surface strike, the ship carries launchers for Type 17 (SSM-2) anti-ship missiles designed to maintain accuracy under electronic countermeasures. Newer variants integrate a Mk 41 vertical launch system with up to 32 cells, enabling the use of Type 03 surface-to-air missiles and Type 07 vertical launch anti-submarine rockets. Close-in defense is provided by a SeaRAM system capable of intercepting incoming threats in the terminal phase, supplemented by torpedo launchers for Type 12 lightweight torpedoes.

The sensor suite is centered on the OPY-2 Active Electronically Scanned Array (AESA) radar, operating in X-band and capable of tracking multiple air, surface, and missile targets simultaneously, while maintaining resistance to jamming. Anti-submarine warfare capabilities rely on the OQQ-25 sonar system combining variable-depth sonar and a towed array, allowing detection at extended ranges, as well as the OQQ-11 sonar for mine detection in littoral environments. These systems are integrated through the OYQ-1 combat management system, while the NOLQ-3E electronic warfare suite provides signal detection, analysis, and countermeasure functions.

Propulsion is based on a Combined Diesel and Gas (CODAG) configuration, incorporating one Rolls-Royce MT30 gas turbine producing around 36 MW and two MAN diesel engines. This setup enables speeds exceeding 30 knots while maintaining an operational range of approximately 10,000 nautical miles. A high level of automation, supported by an integrated platform management system, allows operation with a crew of around 90 personnel, reducing logistical requirements while sustaining operational availability.

A notable feature is the internal mission bay and stern ramp located beneath the flight deck, which enables the deployment of unmanned surface and underwater vehicles as well as rigid-hull inflatable boats. This arrangement supports mine countermeasure operations, reconnaissance tasks, and special missions without reliance on port infrastructure. The flight deck and hangar can accommodate a single SH-60 helicopter, extending the ship’s surveillance and engagement range, particularly in anti-submarine warfare roles.

In operational terms, these frigates are intended to operate alongside Hobart-class destroyers and future Hunter-class frigates, with a growing emphasis on anti-submarine warfare. Their ability to escort naval formations, secure maritime routes, and deploy distributed sensor networks supports a strategy based on sustained presence and layered maritime defense across wide operational areas.

This contract also reflects a broader shift in Japan’s defense export policy. Historically constrained by strict regulations, Tokyo has gradually eased its framework since 2014, allowing the transfer of defense equipment to selected partners. The agreement with Australia represents the largest defense export contract in Japan’s history and indicates an intent to participate more actively in international defense-industrial cooperation.

Beyond procurement, the program highlights a closer alignment between Australia and Japan in a regional environment characterized by increasing naval and undersea activity. By strengthening interoperability and establishing long-term industrial cooperation, both countries aim to secure maritime lines of communication and maintain a balance of power in the Indo-Pacific, where control of the maritime domain remains a central factor in regional stability.

Written By Erwan Halna du Fretay - Defense Analyst, Army Recognition Group
Erwan Halna du Fretay holds a Master’s degree in International Relations and has experience studying conflicts and global arms transfers. His research interests lie in security and strategic studies, particularly the dynamics of the defense industry, the evolution of military technologies, and the strategic transformation of armed forces.