As Southeast Asia becomes ever more entangled in great power competition, the region’s most vital — and least visible — infrastructure faces growing peril. The vulnerabilities of undersea cables, which carry nearly all of Southeast Asia’s internet traffic, are becoming harder to ignore. Recent disruptions in Northern Europe and Taiwan have underscored how easily these critical lifelines can be weaponised in grey-zone competition, where strategic coercion thrives without open conflict.
The deeper challenge for Southeast Asia lies in its structural dependence on foreign powers to build, maintain, and repair these cables — a dependence that is fast becoming a strategic liability.
Beneath the waters of the South China Sea and beyond lies a complex network of fibre-optic cables that form the arteries of Southeast Asia’s digital economy. Nearly every email, financial transaction, and online meeting in the region passes through this invisible infrastructure. Yet, despite their critical importance, these cables remain fragile — susceptible to accidental damage, natural disasters, and deliberate sabotage.
While there is no confirmed case of intentional cable cutting in Southeast Asia, the rising militarisation of maritime spaces and intensifying great power rivalry mean the risk can no longer be dismissed. The South China Sea — already a flashpoint for territorial disputes between China and several ASEAN states — has become a particular area of concern.
Beijing has increasingly asserted control over activities within its self-declared “nine-dash line” claim, tightening approval requirements for the installation and maintenance of undersea cables. In April 2024, a Vietnamese cable-repair crew operating inside Hanoi’s exclusive economic zone was confronted by Chinese coast guard vessels — an incident widely interpreted as coercive pressure on commercial operators. Such episodes raise operational costs, delay essential repairs, and deter investment in infrastructure that is already stretched thin.
Geopolitical competition is not only complicating cable maintenance — it is reshaping who gets to build the infrastructure in the first place. The once-cooperative model that allowed American, Chinese, and regional companies to collaborate on large projects has fractured.
One striking example is the Bay to Bay Express Cable System, designed to connect Hong Kong, Southeast Asia, and the United States. The project was halted when Washington refused to approve a Hong Kong landing point and blocked Chinese participation, citing national security concerns.
Similarly, the Southeast Asia–Japan 2 (SJC2) cable — linking Singapore, Hong Kong, and Japan — faced repeated setbacks. Originally planned to go live in 2020, it only entered service in 2025 after Beijing’s new permit demands forced the consortium to reroute construction through the Philippines and Indonesia. These costly delays reveal how easily geopolitics can disrupt regional connectivity, and how little leverage Southeast Asian governments have over digital infrastructure within their own territories.
For decades, Southeast Asia’s undersea cable networks have reflected the technological and financial dominance of foreign powers. But the strategic calculus is shifting as geopolitical rivalry redefines who can — and cannot — participate.
The United States’ 2020 Clean Network initiative and the 2025 extension of the Federal Communications Commission’s restrictions have effectively barred Chinese companies from involvement in US-owned or US-linked undersea cable projects. Washington has justified these measures as essential to protect data security and counter espionage risks.
For Southeast Asia, which has traditionally pursued a pragmatic, non-aligned approach, this emerging bifurcation poses a stark dilemma. Aligning with a US-led regime may guarantee higher standards of security and maintenance but risks alienating China — the region’s largest trading partner. Conversely, partnering with China under its Digital Silk Road initiative offers cost efficiency and rapid construction but invites scrutiny over surveillance and strategic dependence.
In essence, Southeast Asia may soon have to choose between two competing cable regimes — one led by Washington and another by Beijing — with little room for neutrality.
China’s digital ambitions are clear. Through its Digital Silk Road, Beijing aims to expand its influence across global information networks, backed by state-supported firms like HMN Tech and FiberHome. These companies already have a strong foothold in Southeast Asia, underbidding Western and Japanese competitors through lower prices and faster project delivery.
Despite diplomatic pressure from Washington to avoid Chinese suppliers, many Southeast Asian countries have continued to award contracts to Beijing-backed firms. For emerging economies such as Cambodia, Laos, and Myanmar — where cost remains the overriding factor — China’s financing and technology provide a pragmatic solution.
Yet this cost advantage carries strategic risks. Concerns persist over data privacy, surveillance, and the potential for Beijing to exert control over network infrastructure in times of crisis. Just as concerning are the operational challenges of maintenance in contested waters — where cable repairs could become hostage to geopolitical tensions.
Calls to diversify Southeast Asia’s undersea cable supply chain are growing louder, but meaningful change remains elusive. The global market for undersea cables is concentrated among a handful of players — Japan, the United States, China, France, and Germany — with Japan holding the largest share of Southeast Asian projects at around 41 per cent.
Chinese firms account for roughly 19 per cent of the regional market, followed by the United States at 20 per cent, France at 18 per cent, and Germany at 2 per cent. Despite the rise of Chinese players, US and allied companies still dominate in key routes and systems.
Territorial considerations also influence strategic choices. Unlike China, neither the United States nor its allies make competing sovereignty claims over Southeast Asian waters, meaning cable operations under a US-led system face fewer geopolitical barriers. Losing access to this relatively open regime could expose Southeast Asian states to greater risks, even if Chinese options seem cheaper in the short term.
In the immediate future, continued alignment with the United States and its allies may offer greater security and operational predictability for Southeast Asia’s cable infrastructure. But in the long term, the region must strengthen its own capacity to build, maintain, and manage critical digital assets.
Telecom giants like Singtel (Singapore), PLDT (Philippines), and Telekom Malaysia (Malaysia) are well-positioned to spearhead this transformation. By expanding their technical expertise and investment in regional consortia, Southeast Asian firms could reduce reliance on external powers and assert greater agency in shaping the region’s digital future.
Regional cooperation will also be vital. A collective ASEAN framework for undersea cable security — akin to regional energy or maritime safety initiatives — could pool resources, standardize responses to disruptions, and deter coercive behaviour.
Undersea cables may seem remote from the day-to-day lives of Southeast Asia’s citizens, yet they underpin every aspect of the region’s economy — from banking and trade to healthcare and governance. As competition between Washington and Beijing intensifies, these hidden arteries have become the new front line in the struggle for digital dominance.
