U.S. Navy Deploys USS Canberra Warship and P-8A Aircraft to Philippines for South China Sea Exercise.

U.S. Navy forces, led by the USS Canberra Independence-variant littoral combat ship and a P-8A Poseidon maritime patrol aircraft, have deployed to the Philippines alongside naval forces from seven regional partners, creating a multinational surveillance and coordination presence near contested waters in the South China Sea. Operating from Subic Bay, the deployment strengthens the partners’ ability to track maritime activity and maintain a shared operational picture across a strategically important area.

The combination of surface ships and long-range maritime patrol aircraft expands coverage and enables participating forces to exchange information and coordinate responses across a wide operating area. The deployment highlights the growing operational importance of multinational maritime awareness and interoperability as regional navies seek to monitor increasingly contested waters.

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U.S. Navy Independence-variant littoral combat ship USS Canberra (LCS 30) approaches the harbor at Naval Surface Warfare Center, Port Hueneme Division in California on October 31, 2024, for a Combat Systems Assessment Team event. USS Canberra is now participating in the ADMM-Plus maritime activity centered on Subic Bay in the Philippines alongside a P-8A Poseidon and regional naval forces. File image. (Picture source: U.S. Navy)

The U.S. Navy deployment is part of the ADMM-Plus Experts’ Working Group on Maritime Security Joint Cooperative Activity launched on September 20, 2026, and co-hosted by Japan and the Philippines. Officially focused on maritime cooperation, interoperability, and humanitarian assistance, the multinational naval exercise is taking place in a region where maritime domain awareness, persistent surveillance, and rapid coordination have become increasingly important as encounters between Philippine and Chinese forces continue to shape the South China Sea security environment. Recent U.S., Philippine, and allied maritime activities have already emphasized maritime domain awareness, anti-submarine warfare, replenishment, and shared procedures inside the Philippine exclusive economic zone.

The force assembled around the Philippines is notable for both its size and diversity. U.S. Navy participation includes the Independence-variant littoral combat ship USS Canberra (LCS 30) and a P-8A Poseidon maritime patrol and reconnaissance aircraft. Allied and partner vessels include Japan Maritime Self-Defense Force Hyuga-class helicopter destroyer JS Ise (DDH 182); Indian Navy Shivalik-class stealth multi-role frigate INS Sahyadri (F49) and Kora-class corvette INS Kulish (P63); Philippine Navy Jose Rizal-class frigate BRP Jose Rizal (FFG14) and Tarlac-class landing platform dock BRP Tarlac (LD601); Royal Australian Navy Anzac-class frigate HMAS Perth (FFH 157); Republic of Singapore Navy Independence-class littoral mission vessel RSS Justice; Royal Brunei Navy Darussalam-class offshore patrol vessel KDB Darussalam (06); and Royal New Zealand Navy Anzac-class frigate HMNZS Te Mana (F 111) and Polar-class sustainment vessel HMNZS Aotearoa (A 11).

What this force could monitor and coordinate during a South China Sea crisis matters more than the number of ships alone. The P-8A Poseidon is designed for long-range maritime patrol and reconnaissance, surface surveillance and anti-submarine warfare, allowing it to build a maritime picture across an area far beyond the sensor horizon of individual surface ships. In practical terms, a P-8A can detect and track vessel movements, investigate changes in maritime traffic, and pass information to ships operating elsewhere, giving naval forces a faster and more complete picture of activity developing around disputed waters. The U.S. Navy has repeatedly paired P-8A aircraft with Philippine and allied surface forces in recent maritime activities focused on domain awareness and anti-submarine warfare, underlining the aircraft’s growing role as an airborne surveillance node supporting distributed naval operations.

USS Canberra adds a persistent surface presence suited to operations around coastal and archipelagic waters, while Japan’s JS Ise contributes helicopter operations and substantial command-and-control capacity. Frigates from India, Australia, New Zealand and the Philippines can add their own radar, communications and surface-surveillance coverage, while Singapore and Brunei contribute vessels optimized for maritime security and patrol missions. HMNZS Aotearoa adds an equally important capability: sustainment. A maritime force that can detect activity but cannot remain at sea has limited operational endurance, while a replenishment vessel can help extend the time naval forces remain deployed without returning frequently to port.

That combination illustrates how surveillance could work in a real crisis. A P-8A Poseidon detecting unusual ship movement could extend the maritime picture well beyond what a frigate or patrol vessel could see on its own. Surface combatants positioned closer to the area could then maintain persistent observation, helicopters could investigate contacts beyond the immediate horizon, and command-capable ships could help coordinate information between national forces. A sustainment vessel could support a longer presence if the incident continued for days. The significance lies less in creating a permanent multinational combat formation than in reducing the time required for different navies to understand what is happening and coordinate their movements when events develop quickly.

The Philippine contribution is particularly relevant to that concept. BRP Jose Rizal provides a modern frigate for surveillance and surface operations, while BRP Tarlac adds amphibious lift and the ability to move personnel, vehicles, helicopters, and relief supplies. For the Philippines, operating these ships with U.S., Japanese, Australian, Indian, and other regional naval forces builds experience with partners that can contribute very different capabilities, from long-range maritime surveillance to logistics and command support.

Subic Bay adds strategic weight to the deployment. Located on the western side of Luzon and opening toward the South China Sea, the area provides access to waters leading toward Scarborough Shoal and the northern approaches to the Spratly Islands while remaining connected to important Philippine transport and military infrastructure. U.S., Japanese, and Philippine forces have previously used Subic Bay as a staging point for maritime activities that then moved into the South China Sea, including operations involving a U.S. destroyer, a Philippine frigate, a Japanese amphibious ship, and a P-8A Poseidon.

The location is increasingly important as the United States and its partners emphasize distributed operations rather than dependence on a small number of major military facilities. Ports and airfields in the Philippines can offer additional options for staging, refueling, maintenance, and personnel movement closer to contested waters, while Subic Bay’s position allows naval forces to transition relatively quickly from shore-based coordination to operations in the South China Sea. For the Philippines, this geography also makes maritime surveillance particularly important because incidents west of Luzon can develop close to waters where the country maintains territorial and economic interests.

The humanitarian assistance and disaster-response scenario used for the ADMM-Plus activity remains operationally credible because Southeast Asia is regularly exposed to typhoons, earthquakes, and other natural disasters. Yet the same capabilities required for disaster relief—maritime surveillance, helicopter operations, communications, logistics, ship-to-ship coordination and command and control—are also required during a maritime security emergency. Exercises built around disaster response therefore give participating forces a politically less confrontational framework for practicing procedures that are also relevant if several countries need to respond to a rapidly developing incident at sea.

The multinational composition is therefore strategically more significant than any single maneuver. Australia, Brunei, India, Japan, New Zealand, the Philippines, Singapore and the United States bring together treaty allies, major Indo-Pacific naval powers and ASEAN states in one maritime grouping. Recent U.S.-led exercises in the western Pacific have likewise focused on communications pathways, contact tracking and joint management of complex maritime operations, showing that connecting national command systems and surveillance networks is becoming a recurring priority across the region.

The September activity should not be characterized as preparation for a specific confrontation with China, since its declared objectives remain maritime security, interoperability and disaster response. Its relevance, however, is difficult to separate from the South China Sea environment in which it is taking place. For the Philippines, multinational maritime surveillance and closer coordination with regional naval forces provide additional means to monitor nearby waters, document activity, and communicate rapidly with partners as tensions with China persist.

The wider significance lies in how these capabilities can connect during a crisis. A P-8A Poseidon can extend maritime surveillance far beyond the horizon of individual ships, surface forces can maintain local presence and share contacts, helicopters can investigate activity across a wider area, and sustainment vessels can keep the group operating longer. From Subic Bay, this gives the Philippines and its partners a practical framework for monitoring contested South China Sea waters and coordinating naval forces more quickly if a maritime incident escalates.

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Written by Alain Servaes – Chief Editor, Army Recognition Group
Alain Servaes is a former infantry non-commissioned officer and the founder of Army Recognition. With over 20 years in defense journalism, he provides expert analysis on military equipment, NATO operations, and the global defense industry.