Introduction: A pivotal moment for ASEAN maritime security
The Indo-Pacific’s maritime domain is the backbone of regional security and prosperity. With the Philippines taking the helm of ASEAN in November 2025 under the theme “Navigating Our Future, Together,” there is a timely opportunity to elevate a collective focus on undersea security. The seas around Southeast Asia are not merely lanes for trade; they are theaters where national claims collide, freedom of navigation is tested, and critical options for energy and supply lines are debated. A more robust ASEAN approach to undersea security—led by the Philippines—could help reduce tensions, improve information sharing, and sustain lawful order in an increasingly contested theater.
The stakes: why undersea security matters for ASEAN
Undersea security affects every facet of regional life—from fish stocks and coastal livelihoods to global supply chains and energy security. The South China Sea remains a flashpoint where overlapping claims, militarization, and artificial island construction have tested diplomacy and military restraint. ASEAN’s strength lies in unity and credible conflict management, yet it also requires practical mechanisms for submarine and surface security, cyber-enabled maritime surveillance, and joint exercises that foster interoperability. The Philippines’ chairmanship offers a chance to translate diplomatic commitments into concrete, measurable action on undersea governance.
The Philippines’ strategic advantages and responsibilities
As a frontline maritime state with extensive archipelagic waters, the Philippines possesses unique access to both coastal and offshore security dynamics. Its geographic position enables it to contribute to undersea situational awareness, anti-piracy coordination, and search-and-rescue capabilities. The new chairmanship can push for stronger maritime domain awareness (MDA) sharing, standardized reporting of near-shore incidents, and expanded joint patrols in the Spratly and Scarborough Shoal regions, where risk perception remains high among claimant states.
Responsibility also means promoting the rule of law. ASEAN can advance norms for freedom of navigation, maritime safety, and resource exploitation that align with UNCLOS and international maritime law. Coordinated conflict de-escalation protocols, crisis hotlines, and disaster response coordination should be prioritized to avoid miscalculation in tense standoffs at sea.
Concrete steps to shore up undersea security
First, enhance information-sharing platforms. A regional undersea monitoring framework—integrating satellite data, coastal radar, and marine traffic information—would improve early warning of unusual submarine activity, illicit fishing, or illegal dredging that destabilizes underwater ecosystems and economic zones.
Second, expand joint exercises across navies, coast guards, and marines. Drills focusing on submarine rescue, anti-submarine warfare (ASW) readiness, and anti-ship missile defense can raise readiness without provoking escalation. Third, invest in blue economy safeguards. Protecting submarine cables, offshore energy infrastructure, and deep-sea biodiversity requires cross-border cooperation, including pollution response and environmental impact assessment standards for seabed mining and energy projects.
Fourth, strengthen legal and diplomatic channels. Regular ASEAN-led dialogues with China, Taiwan, the United States, Japan, Australia, and regional partners will be crucial. The goal is to build a code of conduct in practice—fast-track dispute resolution, transparent transparency measures, and confidence-building measures that reduce the risk of misinterpretation in contested waters.
What success would look like
Successful undersea security governance would show tangible outcomes: improved surveillance sharing; more effective maritime patrols; clearer rules of engagement that avoid missteps; and a regional framework for peaceful resource management. The Philippines’ leadership can catalyze a multilateral process that respects sovereignty while ensuring open access to sea lines of communication. This is essential for the region’s economic vitality, given that much of ASEAN’s trade transits through the very waters at the heart of strategic tension.
Conclusion: Navigating our future with stronger undersea security
The Philippines’ ASEAN chairmanship provides a historic opportunity to reframe regional maritime security—from a set of episodic incidents to a sustained, cooperative security architecture. By prioritizing undersea security anchored in law, transparency, and practical cooperation, ASEAN can help secure sea lanes, protect vulnerable communities, and sustain the region’s prosperity. In navigating our future, together, a more secure undersea domain is not just a strategic necessity—it is a shared responsibility that binds all ASEAN member states.
