The Geopolitics of the Seafloor: Securing the World's Submarine Data Cables

In an increasingly interconnected world, the lifeblood of our digital existence flows not through the air, but deep beneath the waves. An astonishing 95% to 99% of all international data is transmitted through a vast network of submarine data cables, thin as a garden hose, snaking across the ocean floor. These undersea conduits are the invisible yet indispensable infrastructure of the 21st century, powering everything from our daily communications and financial transactions to global trade and national security. However, this critical foundation of the modern world is increasingly becoming a focal point of geopolitical competition and a potential theater for conflict.

The Unseen Arteries of the Global Economy

The sheer volume of data coursing through these submarine cables is staggering. Every day, an estimated $10 trillion in financial transactions zip across the globe via this network. This figure underscores the profound economic reliance on the uninterrupted flow of information. Beyond finance, these cables are the backbone for a myriad of activities vital to modern society, including international scientific collaboration, the functioning of cloud services, and the ever-expanding 5G networks. Governments also heavily depend on this privately-owned infrastructure for their own communications, including diplomatic cables and military orders.

This dependence is only set to grow. Global data consumption is projected to triple between 2022 and 2027, driven by the proliferation of artificial intelligence, cloud computing, and other data-intensive technologies. This insatiable demand is fueling a new wave of investment in submarine cable infrastructure, with the global market size expected to grow from USD 18.2 billion in 2024 to USD 29.7 billion by 2029.

A New Arena for Great Power Competition

The "geopolitical honeymoon" of the early internet, characterized by a spirit of shared technological advancement, is over. Today, the seafloor is a new frontier in the strategic competition between global powers, primarily the United States, China, and Russia. This rivalry is transforming the once-neutral domain of submarine cables into a landscape of strategic maneuvering and potential conflict.

The Rise of "Digital Sovereignty"

Nations are increasingly viewing control over data and the infrastructure that carries it as a matter of "AI sovereignty" and a critical component of their national interests. This has led to a "bifurcation" of cable networks, with distinct spheres of influence emerging. The United States and its allies are actively working to prevent the expansion of what they deem high-risk Chinese vendors in submarine networks. In 2020, the White House vetoed a planned subsea cable project by Google and Meta that would have connected to Hong Kong, citing concerns about potential data interception by China. This has pushed companies to reroute new cable systems away from Chinese territories and other areas perceived as vulnerable.

In response, China has been aggressively expanding its own subsea cable capabilities through state-owned companies like HMN Technologies (formerly Huawei Marine). These efforts are part of China's broader "Digital Silk Road" initiative, which aims to enhance its global digital connectivity and influence. This has led to an "underwater geopolitical rivalry," with projects like China's PEACE (Pakistan and East Asia Connecting Europe) cable directly competing with Western-backed initiatives.

Russia has also demonstrated a keen interest in undersea infrastructure, with its naval activities often concentrated around crucial and hard-to-reach cables in the North Atlantic. These actions are seen by NATO and Western nations as a potential threat to transatlantic security.

The Corporate-State Nexus

A significant shift in the submarine cable landscape is the increasing dominance of tech giants like Google, Meta (Facebook), Amazon, and Microsoft. These companies now own or lease around half of all undersea bandwidth worldwide and are major investors in new cable projects. For instance, Google's private Equiano cable stretches from Portugal to South Africa, and Meta's ambitious Project Waterworth aims to connect the US, India, Brazil, and South Africa.

While this private investment adds much-needed redundancy and robustness to the global network, it also blurs the lines between corporate and national interests. Governments often rely on these private companies to advance their geopolitical objectives, as seen in the US government's support for projects that bypass China. This creates a complex dynamic where commercial imperatives and strategic goals are increasingly intertwined.

A Web of Vulnerabilities

The very nature of submarine cables makes them susceptible to a range of threats, both accidental and deliberate.

Physical Threats

The most common cause of cable damage—accounting for 150 to 200 faults annually—is accidental, stemming from commercial fishing and shipping activities, such as dragging anchors. Natural disasters like underwater earthquakes and landslides also pose a significant risk. For example, in March 2024, seismic activity caused major internet disruptions in several West African nations.

Of greater concern is the potential for deliberate sabotage. The sabotage of the Nord Stream gas pipelines in 2022 served as a stark wake-up call, highlighting the vulnerability of all critical undersea infrastructure. Recent incidents have further fueled these fears. In late 2024 and early 2025, a series of cable cuts in the Baltic and Red Seas, as well as around Taiwan, were investigated as potential hostile acts. Chinese vessels have been implicated in severing cables connecting Taiwan to its Matsu islands, raising concerns about "gray zone" tactics designed to intimidate and disrupt.

The strategic placement of such disruptions can have significant consequences, degrading communication capabilities, forcing data traffic onto monitored routes, and creating economic pressure.

Espionage and Cyber Threats

Beyond physical damage, the threat of espionage looms large. There are concerns that nations could tap into fiber-optic cables to intercept vast amounts of data. In 2018, a Chinese wiretapping device was reportedly discovered on a cable near Okinawa, Japan. The involvement of state-controlled companies in the construction and maintenance of cables raises the risk of backdoors being inserted into the infrastructure or at landing stations.

Cyberattacks targeting the network management systems that control data flow are another significant vulnerability. A successful hack could disrupt data flows or even give a malicious actor control over a portion of the network.

The Fragmented Legal Landscape

The international legal framework for protecting submarine cables is complex and, in many ways, inadequate to address modern threats. The 1982 United Nations Convention on the Law of the Sea (UNCLOS) grants all states the freedom to lay submarine cables on the high seas and establishes that damaging a cable is a punishable offense. However, enforcement, particularly in international waters, remains a significant challenge.

There are ongoing discussions about how to strengthen this legal regime. Suggestions include creating cable protection zones, adopting new international treaties, and even classifying attacks on undersea infrastructure as acts of piracy, which would grant universal jurisdiction to apprehend and prosecute offenders.

Securing the Depths: The Path Forward

The growing geopolitical tensions and vulnerabilities surrounding submarine cables demand a multi-faceted approach to security.

International Cooperation and Information Sharing

Enhanced cooperation and intelligence sharing among allied nations are crucial. Initiatives like NATO's Maritime Centre for Security of Critical Underwater Infrastructure and the Quad's framework for cooperation on cable protection are steps in the right direction. Regional partnerships, such as those within ASEAN, are also vital for effective protection.

Technological Solutions and Resilience

Technological advancements can play a key role in enhancing security. Electronic monitoring systems can detect anomalies in the seabed environment, while end-to-end encryption can reduce the risk of surveillance. The use of underwater drones for installation, assessment, and maintenance can also add a layer of security. Building redundancy into the network by diversifying cable routes and investing in new systems is also critical to mitigating the impact of any single point of failure.

Public-Private Partnerships

Given the predominantly private ownership of submarine cables, strong partnerships between governments and the private sector are essential. Governments can provide the security and regulatory frameworks, while private companies bring the investment and technical expertise.

The silent, dark depths of the ocean have become a critical, yet contested, domain in our increasingly digital world. Securing the world's submarine data cables is not just a technical or economic issue; it is a geopolitical imperative. The future of global communication, economic stability, and international security depends on our ability to navigate the complex geopolitics of the seafloor and ensure the resilience of this vital, unseen infrastructure.

The Unseen Arteries of the Global Economy

A New Arena for Great Power Competition

A Web of Vulnerabilities

The Fragmented Legal Landscape

Securing the Depths: The Path Forward

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