Underwater and unprotected: why Asean and the EU must secure subsea lifelines

What does the world’s digital economy rest on? Thousands of kilometres of fibre-optic cable lying on the ocean floor and, increasingly, in the crosshairs of great-power rivalry.The 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”. It has also, however, generated momentum for closer Asean–EU collaboration.Subsea fibre-optic cables carry roughly 99 per cent of intercontinental data traffic, yet this critical infrastructure is highly exposed and has faced repeated disruptions across Europe and the Asia-Pacific.For the Association of Southeast Asian Nations and the European Union, this shared vulnerability opens a pragmatic avenue for enhanced interregional cooperation – one that sidesteps the binary logic of US–China competition by focusing on infrastructure resilience rather than alignment with either power.Asean foreign ministers join hands for a photo during a summit in Kuala Lumpur on October 25, 2025. Photo: EPARecent statements by EU High Representative for Foreign Affairs and Security Policy Kaja Kallas and Singapore’s Defence Minister Chan Chun Sing both highlight that protecting subsea cables increasingly demands that countries far apart work together, “because an attack on one part of such infrastructure is an attack on the entire network”.