The Monthly Roundup: Jocelinn Kang on the rising threat to subsea infrastructure
ASPI Cyber, Technology & Security Program Manager and Technical Specialist Jocelinn Kang writes on the growing contest beneath the waves—and shares her top picks from the Digest this month.
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Welcome to another edition of The Daily Cyber & Tech Digest Monthly Update! Each month, an ASPI expert will share their top news picks and provide their own take on one key story. This month, Jocelinn Kang, Program Manager and Technical Specialist at ASPI CTS, shares her take.
Why subsea infrastructure is now a strategic priority
This month we focus on a surge of underreported but highly significant developments in the world of undersea infrastructure. From the EU unveiling a new cable security plan, to the US military supporting NATO’s expanded monitoring efforts in the Baltic Sea, it’s becoming clear that the security of submarine infrastructure—including data and power cables, energy pipelines and sensor networks—has evolved from a quiet concern within governments, to a pressing national security priority.
For subsea data cables, damage is rather common and typically caused by fishing gear or ship anchors, with around 150–200 repairs each year globally. To reduce the impact on customers, network operators routinely set up alternative data pathways, and the submarine cable industry is well-practiced at repairing cables quickly. Still, in the Baltic Sea region, where Russia’s full-scale invasion of Ukraine in 2022 has heightened tensions, these incidents are occurring amongst a slew of suspicious activity ranging from unusual marine vessel movements to the damage of energy pipelines.
Not all damage is deliberate. In fact, many aren't. Unnamed European officials have reportedly been advised that the number of cable faults has not increased in line with rising maritime traffic in the region. Investigations by Swedish, Finnish, US and European security services have shown that some of the recent high-profile cuts were accidental. Even Chinese and Russian cables have been severed in recent months.
Whether intentional or negligence, the cumulative effect is the same—it’s making governments nervous. These incidents have triggered a wave of international responses across several fronts: national resilience assessments, new governance efforts, maritime patrols, and investment in technological resilience.
In the UK, the Joint Committee on National Security Strategy is assessing how prepared the country is to respond to large-scale cable disruptions. The EU, meanwhile, is implementing a structured policy and investment resilience framework. Its Action Plan on Cable Security released in February, includes mapping submarine cable infrastructure, conducting risk assessments, developing a security framework, and enhancing surveillance and detection capabilities.
Beyond Europe, the International Telecommunications Union is fostering global coordination. The first International Submarine Cable Resilience Summit was held in February where it formed working groups on key cable resilience measures. Further, The concluding Summit Declaration called for cooperation on issues ranging from advancing environmentally sustainable approaches within the submarine cable lifecycle, to preparing for future and present connectivity needs and using data for informed decision-making.
On the military front, NATO is treating undersea infrastructure as a key component of economic warfare. In January it rolled out the Baltic Sentry initiative: a deployment of naval ships, underwater drones, and surveillance aircraft tasked with monitoring the region’s cables and pipelines. In February, US Marines deployed to Finland in support of this NATO-led mission.
Media coverage often fixates on communication cable cuts, and sometimes syndicates articles with overstated narratives around cable cutting technologies that overlook the broader picture of China’s research and development capabilities. Meanwhile the real story lies elsewhere. A wide range of critical infrastructure lies beneath the sea—including gas pipelines, sensor networks, and power cables—and the nature and source of the threats facing them is more complex and ambiguous.
The Nord Stream explosions in 2022 are emblematic of this problem. Once widely suspected to be orchestrated by Russia, in 2024 were reported to have been the work of a pro-Ukrainian group.
A series of subsequent incidents across Europe reinforces this point, including concerns over the potential dual-use of civilian and commercial fleets. On Christmas Day a Russia-linked tanker, Eagle S, severed Finland’s Estlink 2 power cable and four communication cables. While early reports alleged the vessel was carrying high-tech surveillance equipment designed to monitor NATO operations, subsequent investigations by Finnish police cast doubts on these claims and concluded the damage was accidental.
A year earlier, the Balticconnector gas pipeline between Estonia and Finland was damaged by the anchor of a commercial Chinese-owned, Hong Kong-flagged vessel, the Newnew Polar Bear. China conducted an internal investigation and confirmed in August 2024 that the vessel was responsible, attributing the cause to harsh weather conditions. Nonetheless, Estonia and Finland continue to run their own investigation into the matter.
In 2021, the cable connecting sections of Norway’s Lofoten-Vesterålen scientific sensor network, that is capable of monitoring submarine activity, mysteriously disappeared. The recovered cable showed cleanly cut ends, consistent with a power saw. Automatic Identification System (AIS) data pointed to a Russian-flagged fishing trawler, Saami, whose course repeatedly intersected the cable’s location at the time of the outage.
Importantly, these threats aren’t confined to Europe. In the Pacific, Palau, one of Taiwan’s few remaining formal diplomatic partners, has faced repeated incursions by China-linked research and spacecraft tracking vessels. These vessels entered Palau’s Exclusive Economic Zone in 2018, 2021, and 2022. Each time without authorisation, sometimes engaging in questionable manoeuvres over data cables and lingering for days.
These incidents illustrate that the security challenge extends beyond physical destruction to the broader risk of adversaries compromising critical networks and gaining strategic intelligence. Attribution remains difficult — which means deterrence is too.
As governments step up their responses, the challenge will be not just in building critical infrastructure resilience, but in developing norms, robust legal frameworks, and coalitions that can hold bad actors accountable. Without that, we’re likely to see more anchors drop.
My must-reads
ABC Pacific
For those new to the subject, this visually engaging article serves as an excellent introduction. It offers a clear overview of submarine cables in the Indo-Pacific, explaining their critical role in global communications, the vulnerabilities they face, and the intensifying geopolitical rivalry between the US and China. It also draws attention to the smaller nations in the South Pacific that must choose between them.
A drunken evening, a rented yacht: The real story of the Nord Stream Pipeline sabotage
The Wall Journal
An investigative report revealing that private Ukrainian businessmen financed the 2022 Nord Stream sabotage—executed by a small, covert team and overseen by a senior Ukrainian general.
Anchors damaging cables..............is such a drag.
European Subsea Cables Association
A blog post by the European Subsea Cable Association pushing back against the idea that anchor damage is rare or necessarily suspicious. It highlights numerous examples of erratic maritime behaviour causing damage.
This article challenges the alarmist interpretations surrounding China's development of deep-sea cable-cutting technology. It argues that the public revelation of such advancements is less about the technology and more about strategic signalling. The author encourages policy makers to critically assess the narratives that often accompany reports on geopolitically-linked technological developments.
