Introduction: A Call to Strengthen ASEAN’s Undersea Security
The Philippines, as chair of the Association of Southeast Asian Nations (ASEAN) for 2025, has a pivotal opportunity to sharpen the bloc’s maritime security posture. With growing undersea activity, intricate disputes in the South China Sea, and evolving challenges posed by major powers, ensuring safe and stable sea lines of communication is no longer optional for ASEAN. The call for a focused approach to undersea security aligns with the Philippines’ chairmanship theme of “Navigating Our Future, Together” and resonates with regional expectations for peaceful, rules-based competition in the maritime domain.
Why Undersea Security Matters Now
Undersea security encompasses more than anti-submarine warfare. It includes resilient seabed infrastructure, data cables, navigational freedom, fisheries governance, and coastline protection. The undersea environment is vital for regional economic growth, digital connectivity, and security architecture. As vital cables route through Southeast Asia and the wider Indo-Pacific, any disruption—whether intentional or accidental—can ripple through economies and daily life. ASEAN’s challenge is to deter coercion, prevent escalation, and establish norms that reduce miscalculation in an area where many claims overlap.
Philippine Leadership and the ASEAN Chairmanship
President Ferdinand Marcos Jr.’s launch of ASEAN Chairship on 14 November 2025 foregrounded peace and security anchors, prosperity, and inclusive growth. The focus on undersea security would symbolize a practical, tangible deliverable for ASEAN: a coordinated maritime security framework, combined exercises, information-sharing channels, and joint resilience-building for critical sea lanes. As the Philippines combines diplomatic outreach with practical defense diplomacy, it can leverage existing mechanisms—such as ASEAN Regional Forum (ARF) dialogues and the ASEAN Defence Ministers’ Meetings-Plus (ADMM-Plus)—to advance collective action and build trust among members and partners.
Strategic Pillars for an ASEAN Undersea Security Framework
1) Norms and rules: Establish shared norms to govern undersea activity, from submarine cables to seabed mining, reducing ambiguity in contested zones.
2) Information sharing: Create a regional intelligence and surveillance-sharing platform focused on maritime domain awareness, to identify threats and prevent incidents before they escalate.
3) Joint exercises: Expand and deepen navally focused exercises and search-and-rescue (SAR) drills, including anti-submarine and anti-ship training, with mixed-capability participation to raise the baseline of readiness in all member states.
4) Infrastructure resilience: Protect critical maritime infrastructure—ports, cables, data centers, and offshore energy facilities—through risk assessment, redundancy planning, and rapid-response protocols.
5) Rule of law: Promote dispute resolution through international law, including UNCLOS, and support peaceful settlements in line with regional commitments.
Balancing Regional Security with Strategic Competition
ASEAN’s strength lies in unity amid great-power competition. The Philippines can facilitate a balanced approach that avoids antagonizing any single power while ensuring that regional norms are respected. This requires transparent diplomacy, predictable behavior at sea, and a clear stance against coercive actions in chokepoints and commonly used routes. By anchoring undersea security in mediation, legal frameworks, and cooperative actions, ASEAN can safeguard sea lanes without letting geopolitical tensions derail cooperative security gains.
Practical Steps for Immediate Action
• Initiate a Southeast Asia Undersea Security Protocol that outlines preventive measures for incidents near critical undersea infrastructure.
• Form a regional working group to map undersea assets and vulnerabilities, including cables and energy pipelines, with routine risk assessments.
• Launch a joint maritime security information exchange that respects data sovereignty while enabling timely alerts on disruptions.
• Schedule a biennial ASEAN-wide undersea security exercise, with partner observers and industry stakeholders to test redundancy and response plans.
• Engage civil society and academic institutions to study maritime governance, environmental protection, and fisheries, ensuring a holistic security approach.
Conclusion: A Shared Path Forward
The Philippines’ leadership in ASEAN should translate rhetorical commitments into concrete, practical steps that fortify undersea security. Doing so will enhance regional resilience, protect critical infrastructure, and sustain the free flow of commerce that underpins Southeast Asia’s prosperity. As ASEAN navigates a complex strategic landscape, a robust undersea security framework offers a stable, rules-based pathway for the region’s future, built “together” with allies and partners who share a commitment to peace, law, and stability across the seas.
