Enhancing ASEAN–EU Cooperation on Subsea Cable Security

A confluence of recent subsea cable disruptions, gaps in the 1982 UN Convention on the Law of the Sea (UNCLOS), and intensifying great power competition has elevated this underwater infrastructure from a technical and commercial concern to a security issue, characterised as “this century’s hidden battleground”. Yet it has also produced momentum for closer ASEAN–EU collaboration.

Subsea fibre-optic cables carry about 99 per cent of intercontinental data traffic. Yet this critical infrastructure is highly exposed and has faced several disruptions in both Europe and the Asia-Pacific. For ASEAN and the EU, this shared vulnerability opens a pragmatic avenue for enhanced interregional cooperation that bypasses the binary logic of US–China competition by focusing on infrastructure resilience rather than alignment with either power. Recent statements by EU High Representative for Foreign Affairs and Security Policy Kaja Kallas and Singapore’s Minister for Defence Chan Chun Sing underscore that protecting subsea cables increasingly demands countries far apart to work together “because an attack on one part of such infrastructure is an attack on the entire network”.

The US–China competition is simultaneously securitising and fragmenting the subsea cable landscape. The US has restricted the use of Chinese technology and the participation of entities designated as “foreign adversaries” in US subsea cable projects. China, for its part, is supporting its telecommunication firms in delivering low-cost submarine cable systems. It has also developed an advanced cable-cutting device that can disrupt undersea networks. For Southeast Asian states, a potential split of the cable market into competing US- and China-aligned segments could narrow the pool of available suppliers, raise infrastructure costs, and constrain sovereign choice over cable partnerships.

Furthermore, the legal regime governing submarine cables in UNCLOS is widely regarded as insufficient. It allocates primary enforcement responsibility for cable damage beyond territorial seas to flag states, but most states have not adopted laws criminalising acts outside their jurisdiction committed by ships bearing their flags. When a vessel damages a cable in another state’s exclusive economic zone, the victim state has limited legal recourse. The difficulty of determining whether cable damage is due to sabotage or negligence further erodes accountability and is compounded by UNCLOS’s lack of any systematic international investigation mechanism.

Finally, ASEAN–EU cooperation on subsea cables matters because their different threat perceptions create complementarity. Treating subsea cables as critical infrastructure primarily in a context of hybrid threats and growing geopolitical competition, the EU has responded with binding regulations, dedicated funding, and a cable security action plan. ASEAN’s threat perception centres more on operational risks and natural hazards, as well as great power pressure that risks limiting ASEAN states’ room to choose their own infrastructure partners. It has responded with resilience and repair guidelines and incremental regional coordination rather than a joint operational response mechanism. These different starting points mean each side has built tools the other lacks. Partnering with the EU therefore allows ASEAN to selectively draw on European regulatory and technical instruments while retaining its strategic autonomy. It also gives the EU a concrete way to extend its cable security agenda to a key transit region that it has so far engaged only partially in this issue area.

The task now is to translate declarations and broad initiatives into concrete legal and operational commitments to ensure that subsea cables become a resilient backbone of the digital economy, not its Achilles heel.

On the EU side, the NIS2 Directive and the Critical Entities Resilience Directive, both adopted in 2022, provide an internal framework for resilience of critical infrastructure, including subsea cables. The 2025 EU Action Plan on Cable Security is accompanied by funding commitments totalling almost EUR1 billion for investments in digital backbone infrastructure and calls for “advanced cable diplomacy” with partners, including in the Indo-Pacific. However, the EU’s submarine cable projects remain focused on Africa, the Mediterranean, and the Black Sea. The most notable EU-linked initiative towards Asia, the Far North Fiber project connecting Europe and Japan via the Arctic, bypasses Southeast Asia, and the EU-ASEAN cable relationship remains limited.

On the ASEAN side, regional frameworks have evolved from the 2019 Guidelines for Strengthening Resilience and Repair of Submarine Cables to Enhanced Guidelines in 2026, complemented by the ASEAN Working Group on Submarine Cables established in 2024 and the ADMM’s 2025 Concept Paper, which frames intentional cable damage as a maritime security challenge. Yet these efforts are mostly incremental, and ASEAN still has no dedicated joint operational mechanism for cable incident response.

At the interregional level, cooperation is channelled through the ASEAN-EU Plan of Action (2023–2027), the 2026 ASEAN-EU Digital Work Plan, and the bilateral EU-Singapore Digital Partnership, which represent non-binding cooperative frameworks under which subsea cable cooperation can be pursued. This patchwork creates both gaps and room for legal and institutional innovation.

Bridging the gaps requires strengthening existing instruments and moving towards operationally grounded cooperation. Lynn Kuok proposes an ASEAN rule book adapted from EU regulatory frameworks and a regional coordination centre that could build on Singapore’s Information Fusion Centre for joint threat assessment and incident response.

A second avenue could be an ASEAN–EU repair capacity-sharing arrangement, extending the EU’s planned Cable Vessels Reserve Fleet to ASEAN partners.

Supply chain cooperation offers another entry point, given ASEAN states’ interest in keeping a diverse mix of cable suppliers rather than sliding into a US–China binary. European firms, notably France’s Alcatel Submarine Networks, are among the global leaders in cable manufacturing and installation and are involved in major systems connecting Southeast Asia. Deepening these commercial relationships into more structured resilience partnerships, for instance, on maintenance, repair, and cable monitoring, would remain commercially grounded rather than overtly geopolitical, making them easier for both sides to sustain.

These proposals recognise that the EU’s value to ASEAN in this area lies not in exporting its model wholesale, but in providing modular regulatory and operational tools that ASEAN states can adapt to their own institutional contexts. The key is tailoring cooperation to what is politically feasible and where immediate gains are clearest. The task now is to translate declarations and broad initiatives into concrete legal and operational commitments to ensure that subsea cables become a resilient backbone of the digital economy, not its Achilles heel.

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