The Philippines should shore up ASEAN’s undersea security

Department of Research, Strategic Studies and International Relations 13-01-2026

The Philippines’ 2026 ASEAN chairmanship comes as regional stability is under strain and undersea governance is becoming more urgent. Undersea cables underpin connectivity, but intensifying US–China competition is widening security gaps. ASEAN leaders recognise gaps, yet cooperation remains largely bilateral and fragmented. Manila should use its term as ASEAN Chair to strengthen regional mechanisms, elevate working groups, update the ASEAN Maritime Outlook, institutionalise joint patrols and build capacity.

On 14 November 2025, Philippine President Ferdinand Marcos Jr officially launchedt the Philippines ‘ ASEAN chairship  under the theme ‘Navigating Our Future, Together’. He declared that the chairship will focus on peace and security anchors, prosperity corridors and people empowerment.

Manila takes over as ASEAN chair at a time when the international system is fragmenting. Yet just as ASEAN is most needed, the organisation’s role in regional stability is increasingly under strain. Negotiations on a South China Sea code of conduct  have stalled, Myanmar’s junta continues to ignore ASEAN’s five -point consensus and the Thailand–Cambodia conflict continues to flare. ASEAN must prove that it can still shape regional dynamics — and one issue of increasing importance is  undersea governance.

Across the region, countries are rapidly expanding undersea cable networks that underpin global communications and internet connectivity. At the same time, US–China competition over the control and security of these cables is intensifying, leaving ASEAN members exposed unless they coordinate their response. Maritime issues ASEAN’s landlocked and maritime states, but undersea governance presents an opportunity to strengthen collective governance and mitigate outside influence.

In early September, China used a military parade commemorating the end of the Second World War to showcase its new naval drones, highlighting its expanding undersea surveillance and mining capabilities. China has also demonstrated its ability and willingness to interfere with undersea cables. In 2025, Taiwan reported five incidents of cable cutting and  jailed a ship captain over one case — the first such arrest.

The United States is increasingly prioritising enhancing its own and its regional partners’ capacity for undersea military operations in Asia, most prominently through the  AUKUS agreement  Pillar One of the agreement aims to provide Australia with three second-hand nuclear-powered attack submarines by 2032. Pillar Two enhances US collaboration with the United Kingdom, Australia and others on advanced technologies, including undersea robotics. Even before the submarines are delivered, the United States and Australia are taking steps to strengthen undersea capabilities, including through US access to the Henderson  shipyard  near Perth.

As the undersea domain emerges as a ontested area between China and the United States, ASEAN leaders are increasingly conscious of the challenges they face in fully monitoring and managing these developments.

East Asia Forum