Military researchers say the submarine cable network carrying 99 per cent of global intercontinental data traffic and supporting an estimated US$10 trillion in daily cross-border financial transactions is becoming increasingly vulnerable as advances in uncrewed underwater technology lower the barriers to undersea warfare, transforming the seabed into a new arena of strategic competition.
The vast network of submarine cables that underpins the global digital economy is entering what Chinese military researchers describe as a new phase of vulnerability, as technological advances make it increasingly feasible for low-cost uncrewed systems to operate beneath the world’s oceans. In an assessment published in Science and Technology Daily, researchers from China’s National Defence University argue that the seabed, once regarded as difficult to access and prohibitively expensive to control, is rapidly becoming a focal point of strategic competition among major powers.
Their warning centres on the growing accessibility of unmanned undersea vehicles (UUVs), which they say are fundamentally changing the nature of underwater operations. According to Shi Guanglei and Shi Haiming, the traditional dominance of crewed submarines in undersea missions imposed significant financial costs and operational risks, limiting the ability of smaller states to engage in underwater military activities. The emergence of smaller, lower-cost autonomous systems, they contend, has altered that equation.
“The barrier to entry for undersea warfare is lowering,” the researchers wrote, identifying the Aukus security partnership between Australia, Britain and the United States as a significant factor accelerating this transformation. They argued that technological development under the trilateral alliance is contributing to an environment in which seabed operations become more widespread, more persistent and increasingly integrated into military planning.
The researchers described small and medium-sized UUVs as inexpensive, capable of rapid deployment in large numbers and free from the personnel risks associated with crewed platforms. These characteristics, they argued, make it possible for countries to expand their presence on the seabed in ways that were previously beyond their reach.
Their assessment carries implications far beyond military strategy because the infrastructure resting on the ocean floor forms one of the foundations of the modern global economy. According to the article, undersea optical cables carry 99 per cent of intercontinental data traffic, enabling the online services, communications and financial systems that support an estimated US$10 trillion in daily cross-border transactions.
The scale of that infrastructure is immense. Most transcontinental internet traffic moves through approximately 1.7 million kilometres (1 million miles) of fibre-optic submarine cables spanning the world’s oceans. The system is extensive but not immune to disruption. Around 150 to 200 subsea cable faults occur globally each year, illustrating both the complexity of maintaining the network and the challenges of protecting infrastructure spread across vast underwater distances.
Against that backdrop, the researchers argued that submarine cables and underwater pipelines have become increasingly attractive targets. They cited the 2022 sabotage of the Nord Stream natural gas pipelines linking Russia and Germany as an example of the vulnerability of critical underwater infrastructure. They also referred to the disruption to internet services after submarine cables in the Red Sea were cut last year, highlighting how damage to seabed infrastructure can have immediate and widespread consequences for communications and connectivity.
While acknowledging the possibility of deliberate attacks, the broader picture presented by organisations monitoring the cable network remains more nuanced. The International Cable Protection Committee, a Britain-based non-profit organisation, has stated that accidental damage continues to account for the overwhelming majority of submarine cable faults.
According to the organisation’s website, although state-sponsored sabotage remains a recognised risk, accidental damage is “the predominant cause of damage to submarine cables”. It also notes that, “Anecdotally we believe that there have not been verified incidents of state-sponsored sabotage since World War II.” That assessment places recent concerns about intentional attacks alongside the longstanding reality that routine faults continue to arise from non-hostile causes.
The Chinese researchers nevertheless argue that the strategic environment is evolving rapidly. They point to an agreement reached by the Aukus alliance in May to develop UUVs capable of protecting underwater infrastructure while also conducting surveillance, reconnaissance and anti-submarine operations. In their view, the initiative extends well beyond defensive applications.
They contend that the programme “paves the way for future cross-domain joint operations” and argue that the alliance is using the protection of submarine cables as a framework for broader technological development. “Under the guise of ‘protecting submarine cables’ to advance equipment development, Aukus is building a routine seabed monitoring network through uncrewed equipment to gain global underwater situational awareness and seek military strategic advantages in the deep sea,” the researchers wrote.
Their analysis portrays the evolution of UUVs as more than an incremental technological improvement. Rather, they argue that autonomous underwater systems are shifting from supporting reconnaissance missions to becoming independent combat platforms, a transition they say “fundamentally rewrites the logic of underwater warfare”.
Artificial intelligence features prominently in that assessment. The researchers argue that advances in AI will enable future generations of underwater drones to operate autonomously for weeks without requiring constant communication with operators. Such extended autonomous operations would reduce the need to transmit or receive data continuously, lowering the chances of detection while allowing vehicles to remain deployed for prolonged periods.
Looking further ahead, the researchers envisage increasingly sophisticated networks of autonomous underwater systems working together. They describe the possibility of “undersea wolf packs” consisting of dozens or even hundreds of coordinated UUVs capable of patrolling submarine cable routes while also conducting search missions or ambush operations.
These autonomous formations, they suggest, could eventually operate alongside underwater sensor networks and integrate with uncrewed surface and aerial vessels. Such coordination across multiple domains, they argue, points towards new forms of maritime warfare in which autonomous systems collectively monitor, protect and potentially contest access to the seabed.
As dependence on submarine cables continues to underpin global communications, digital services and international commerce, the Chinese researchers argue that technological advances are changing not only how undersea infrastructure is protected but also how it may be contested. Their assessment reflects a view that the seabed, once considered a strategic blind spot because of the difficulty and cost of operating there, is emerging as a central arena in an evolving competition shaped by autonomous technologies, expanding surveillance capabilities and the growing strategic significance of the world’s underwater infrastructure.
