The development of Balabac Island under the U.S.-Philippines Enhanced Defense Cooperation Agreement (EDCA) represents a concrete move in Manila’s strategy to safeguard its sovereign rights in the West Philippine Sea (WPS). However, this U.S.-focused buildup is only part of the picture. The Philippines has intentionally broadened its defense partnerships, building a strong and swiftly evolving alliance with Japan that complements—rather than rivals—the long-established American treaty relationship. Together, these two alliances form a layered deterrence framework that enhances Philippine security far more effectively than either alliance could on its own.
Fresh confirmation today highlights a significant development: for the first time, Japan is deploying a full military contingent to the Philippines for the upcoming “Balikatan 2026” exercises. Japan will be the third-largest participant after the United States and the Philippines. The deployment includes approximately 1,400 personnel, the helicopter carrier JS Ise—one of Japan’s largest warships—the landing ship JS Shimokita, the destroyer JS Ikazuchi, C-130H Hercules transport aircraft, and Type 88 anti-ship missile systems. This represents Japan’s first major combat unit deployment since the 2025 Reciprocal Access Agreement (RAA) came into effect. Previously, the Japan Self-Defense Forces had only participated as observers or in limited humanitarian roles. The exercises, scheduled from April 20 to May 8, will feature over 17,000 troops, including combat forces from Australia, Canada, France, and New Zealand.
The evidence from 2025–2026 is clear: closer cooperation with both Washington and Tokyo has strengthened the Armed Forces of the Philippines (AFP), increased the costs of Chinese gray-zone aggression, and boosted disaster resilience. Both partnerships offer significant benefits to the Philippines. Japan’s role, though more recent and centered on capacity-building and interoperability, provides essential depth, advanced technology, and regional credibility without the historical sensitivities often associated with the U.S. presence.
U.S.-Philippines Alliance: The Cornerstone of a Lasting Partnership
The 1951 Mutual Defense Treaty (MDT) continues to serve as the foundation of the alliance, committing the U.S. to consider any armed attack on Philippine forces, vessels, or aircraft in the Pacific—including the West Philippine Sea—as an attack on the United States itself. The 1999 Visiting Forces Agreement (VFA), along with the 2014 Enhanced Defense Cooperation Agreement (EDCA), establishes the operational framework for the rotational presence and access of U.S. forces.
Key Components of the Current U.S. Military Buildup:
- Nine EDCA sites, including the recent additions in northern Luzon and Balabac Island in Palawan, enabling joint training, prepositioning of equipment, and rapid response.
- Substantial U.S. funding for infrastructure upgrades, fuel storage, runways, and command systems—hundreds of millions committed in recent years.
- Large-scale exercises like Balikatan, which have grown dramatically in scope and now routinely incorporate high-end systems such as anti-ship missiles.
- Intelligence sharing, maritime domain awareness, and direct support for AFP modernization.
This framework provides immediate deterrence by showcasing a visible rotational presence and robust logistical support, increasing the risks of sustained Chinese coercion through clear signals of credible U.S. commitment under the MDT. It also fills the post-1992 capability gap that left the Philippines exposed following the closure of major U.S. bases.
Japan-Philippines Partnership: The Emerging Strategic Complement
Japan’s engagement has accelerated dramatically under President Ferdinand Marcos Jr., evolving from development aid and Coast Guard support into a full-fledged defense partnership. Unlike the U.S. treaty alliance, Japan’s cooperation is framed as a “strategic partnership” and “quasi-alliance,” constrained by Japan’s constitutional limits but increasingly proactive in the Indo-Pacific.
Milestones in 2024–2026:
- Reciprocal Access Agreement (RAA): Signed in July 2024, ratified, and entered into force in September 2025. This allows Japanese Self-Defense Forces (JSDF) and AFP personnel to visit each other’s territory for joint training, exercises, and disaster response—Tokyo’s first such pact with a Southeast Asian nation. It explicitly does not permit permanent bases.
- Acquisition and Cross-Servicing Agreement (ACSA): Signed January 15, 2026, enabling tax-free exchange of ammunition, fuel, food, and services during joint activities, exercises, or humanitarian operations. This directly supports smoother implementation of the RAA.
- Official Security Assistance (OSA): Japan has become a leading donor, providing coastal radars, rigid-hulled inflatable boats (RHIBs), boathouses, slipways, and other maritime assets. Recent commitments include $6 million for facilities and broader equipment transfers.
- Joint and trilateral activities: As highlighted in today’s announcement for Balikatan 2026, Japanese forces are now deploying major naval assets and combat systems alongside U.S. and Philippine troops. This builds directly on the 2025 RAA and demonstrates Tokyo’s willingness to move beyond observer status into operational integration.
Japan’s contributions focus on practical capacity-building, including surveillance, patrol vessels, training, and enhancing interoperability to support WPS patrols and EEZ enforcement. Tokyo’s goals closely align with Manila’s: securing sea lanes, countering Chinese assertiveness, and upholding a rules-based order. Additionally, Japan offers advanced technology and regional credibility as a non-treaty partner.
Side-by-Side Comparison: Scale, Nature, and Impact
- Legal and Structural Depth: The U.S. alliance features a mutual defense commitment (MDT) with clear treaty obligations, backed by EDCA’s facility access and prepositioning rights. Japan’s RAA + ACSA focus on reciprocal visits and logistics support for training/disaster response, without mutual defense guarantees or permanent basing. The U.S. provides broader, more immediate operational depth; Japan offers agile, complementary access.
- Presence and Activities: U.S. rotational forces operate across multiple EDCA sites with significant prepositioned stocks and large exercises. Japanese access is more exercise- and training-oriented, with growing but still rotational deployments—now exemplified by the full contingent and major warships in Balikatan 2026. No Japanese “bases” exist, mirroring the Philippine emphasis on sovereignty under both partnerships.
- Capacity Building and Equipment: The U.S. delivers high-volume funding and advanced systems. Japan excels in targeted maritime security aid—radars, patrol boats, and infrastructure—that bolsters the Philippine Coast Guard and Navy without heavy fiscal burden on Manila. Both accelerate AFP modernization, but Japan’s OSA fills gaps in coastal surveillance and small-craft capabilities, while its anti-ship missiles and naval assets in Balikatan add immediate tactical punch.
- Deterrence Effect: U.S. presence raises escalation thresholds through treaty-backed credibility and logistical reach. Japan adds a second layer of deterrence by complicating Chinese planning across the first island chain, enhancing multilateral signaling (e.g., trilateral U.S.-Japan-Philippines drills and the expanded Balikatan lineup), and demonstrating that aggression faces coordinated pushback from multiple capable partners. Together, they create a “force multiplier” effect—especially timely as drills kick off next week with over 17,000 troops.
- Sovereignty and Domestic Considerations: Both respect Philippine ownership of facilities and rotational (not permanent) presence. Japan’s partnership often faces fewer historical or political sensitivities in the Philippines, allowing smoother public and legislative support.
- Disaster Response and Broader Benefits: Both enhance humanitarian assistance and disaster relief (HADR)—a Philippine priority given frequent typhoons. Japan’s track record in this area is particularly strong.
Overall Security Impact and Strategic Synergy
The combined U.S.-Japan partnership has significantly enhanced Philippine security. While Chinese provocations in the West Philippine Sea continue, the expanding network of joint exercises, shared intelligence, and capability upgrades—now underscored by Japan’s combat deployment in Balikatan 2026—raises the costs of any aggressive escalation or blockade for Beijing. The Armed Forces of the Philippines benefit from training, advanced technology, and operational experience that their budget alone could not rapidly deliver. Public support for these alliances remains strong, reflecting widespread recognition that credible external partnerships are vital as domestic modernization efforts progress.
Critics may raise concerns about entanglement in great-power rivalry, but the alternative—strategic isolation or over-reliance on accommodation—has repeatedly failed to curb Chinese actions, as seen during periods of warmer Beijing-Manila ties. Diversification across like-minded partners reduces dependency risks and strengthens Manila’s diplomatic leverage.
Strongly Advantageous Alliances—With Japan as a Vital Complement to the U.S. Core
The U.S. alliance provides the indispensable treaty-backed deterrent and scale that no other partner can match. Japan’s rapidly deepening partnership adds agility, specialized maritime tools, technological edge, and trilateral synergy that amplify overall resilience without supplanting the American foundation. Far from a choice between them, the Philippines benefits most from weaving both into a coherent strategy—now on vivid display as Japanese warships and missiles integrate into Balikatan alongside U.S. forces.
Balabac’s development under EDCA becomes even more strategically significant when combined with Japanese-supported patrols, joint exercises near the Bashi Channel, and OSA-funded resources. This dual approach provides crucial time for the AFP to build self-reliance while effectively deterring aggression. Manila should prioritize accelerating the implementation of both frameworks—enhancing trilateral cooperation, defining interoperability protocols clearly, and openly documenting Chinese provocations.
In a region shaped by power imbalances favoring revisionist actors, alliances with the United States and Japan represent pragmatic realism rather than subservience. These partnerships bolster Philippine sovereignty, protect crucial economic routes in the West Philippine Sea, and position the country as a proactive defender of regional stability. This strategic buildup is showing tangible results. Sustaining and strengthening these alliances is not just advantageous—it is the most practical path toward a safer, more secure Philippines.