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Japan and U.S. Stage Major Naval Show of Force in Philippine Sea Amid Shifting Defense Strategy.
Japan and the United States launched the ANNUALEX 2025 naval exercise in the Philippine Sea on October 20, testing combined maritime and air combat readiness. The large-scale drills highlight Japan’s shift toward a more assertive defense stance and the allies’ preparation for potential regional crises.
On 20 October 2025, large-scale naval drills ANNUALEX 2025 unfolded in the Philippine Sea, as reported by Commander, U.S. 7th Fleet Public Affairs. The exercise showcases Japan’s clear shift under Prime Minister Takaichi toward a more assertive defense posture, moving beyond post-war restraint in the face of intensifying regional pressure. Conducted under Japan Maritime Self-Defense Force leadership with strong U.S. participation, the drills are designed to stress-test allied combat readiness at sea and in the air. The event matters strategically because it aligns allied capabilities, logistics, and command networks for rapid crisis response across the Western Pacific.
ANNUALEX 2025 featured advanced defense assets including the F-35B Lightning II stealth fighters, Arleigh Burke and Ticonderoga-class warships, P-8A Poseidon patrol aircraft, and the Izumo-class destroyer JS Kaga, all integrated to enhance allied air, surface, and undersea warfare capabilities (Picture Source: U.S. Navy)
At the core of this iteration is a multilateral architecture built around JMSDF command and the helicopter-capable, anti-submarine warfare destroyer JS Kaga (DDH 184), reflecting Japan’s emphasis on sea control, undersea denial, and air-maritime integration. Kaga’s participation underscores a broader JMSDF modernization path that prioritizes persistent aviation, anti-submarine sensors, and deck operations to protect sea lines of communication and to contribute to coalition air defense umbrellas. The U.S. contribution includes the Arleigh Burke–class guided-missile destroyer USS Shoup (DDG 86) and the Ticonderoga-class guided-missile cruiser USS Robert Smalls (CG 62), providing layered air and missile defense with Aegis combat systems and long-range surface strike options. A U.S. Navy submarine adds covert ISR and anti-ship/antisubmarine strike capacity, while P-8A Poseidon maritime patrol aircraft expand the allied undersea surveillance and targeting web across a vast operating area.
The air component is strengthened by U.S. Marine Corps F-35B Lightning II jets from VMFA-242, whose sensor fusion and data-linking elevate the force’s common operating picture. Air and sea logistics, a perennial constraint in wide-ocean operations, are deliberately exercised through the Lewis and Clark–class dry cargo ships USNS Amelia Earhart (T-AKE 6) and USNS Wally Schirra (T-AKE 8), and the fleet oiler USNS Tippecanoe (T-AO 199). Replenishment-at-sea serials validate the fleet’s ability to sustain tempo and presence. Allied breadth is visible as the Royal Australian Navy and Air Force, Royal Canadian Navy and Air Force, the French Navy, and the Royal New Zealand Air Force integrate into formations and mission packages, enlarging the coalition’s radar horizon, ASW sonobuoy fields, and escort density. This allied mosaic is not merely symbolic: it complicates an adversary’s targeting calculus by multiplying sensors, shooters, and decoys under interoperable doctrine.
Operationally, ANNUALEX 2025 concentrates on maritime communications discipline, anti-submarine warfare, and air warfare operations, three pillars for contested-sea campaigning. Communications drills refine emission control and resilient data-sharing in a degraded environment, while combined ASW flights knit together P-8A sensors, shipboard towed arrays, and helicopter dipping sonars to prosecute mobile undersea threats. Air warfare events stress Aegis cueing, cooperative engagement, and joint fires coordination with fifth-generation aircraft, shaping an air-defense grid capable of countering cruise, ballistic, and low-observable threats. Replenishment-at-sea sequences ensure the task force can maintain pressure without returning to port, a prerequisite for deterrence patrols and prolonged crisis management.
The strategic implications are threefold. Geopolitically, the drills signal allied cohesion and the credibility of security guarantees amid intensified competition and coercive maritime behavior. Geostrategically, staging in the Philippine Sea places the force astride key approaches to the First and Second Island Chains, enhancing the allies’ ability to screen chokepoints, protect logistics arcs, and maneuver between theaters without ceding initiative. Militarily, the exercise raises the bar for multi-domain kill chains by pairing survivable surface combatants and submarines with networked aviation and robust afloat sustainment, reinforcing a deterrent posture that is difficult to disaggregate or degrade. Japan’s leadership role is particularly notable: by hosting and commanding a complex, biennial drill and fielding capital assets such as Kaga, Tokyo demonstrates that its defense reforms are translating into deployable operational power, not just plans and budgets.
Context from recent cycles adds weight. The previous ANNUALEX in November 2023 featured Carrier Strike Group 1 centered on USS Carl Vinson (CVN 70), highlighting carrier-led air superiority and sea control under U.S. 7th Fleet, the Navy’s largest forward-deployed numbered fleet, which routinely operates with regional partners to preserve a free and open Indo-Pacific. The 2025 edition leans into coalition ASW, air defense integration, and endurance logistics, reflecting lessons learned and an evolving threat environment that prioritizes distributed, resilient maritime operations.
ANNUALEX 2025 therefore does more than rehearse procedures; it operationalizes a collective deterrent where Japan and the United States, flanked by key allies, can detect earlier, decide faster, and act together at range. As Japan under Prime Minister Takaichi moves decisively beyond post-war pacifism, the Philippine Sea becomes both a training ground and a strategic message: allied naval power is organized, sustained, and ready to hold the initiative in the Indo-Pacific.
Written by Teoman S. Nicanci – Defense Analyst, Army Recognition Group
Teoman S. Nicanci holds degrees in Political Science, Comparative and International Politics, and International Relations and Diplomacy from leading Belgian universities, with research focused on Russian strategic behavior, defense technology, and modern warfare. He is a defense analyst at Army Recognition, specializing in the global defense industry, military armament, and emerging defense technologies.