Undersea cables have long been at the heart of geopolitical competition. Even before the digital age, they carried communications that sustained empires. Today, cables form the backbone of the global digital economy and have re-emerged as points of vulnerability, particularly in the context of what is often described as grey-zone conflict.
Unlike conventional warfare, these operations remain below the threshold of open confrontation, making them harder to attribute and respond to. Incidents involving cable disruptions, whether in the Mediterranean in 2008 or more recently in the Red Sea, have shown how fragile global connectivity can be.
For India too, its rise as a digital power rests on cable infrastructure. The Indian Ocean is home to a dense network of undersea cables that carry over 95 per cent of global data traffic and the overwhelming majority of India’s international connectivity. Finance, governance, defence communications, and the everyday digital economy depend on these cables. Sitting between Europe, the Middle East, and Southeast Asia, India is both a major consumer and a critical transit hub. Cable systems such as the SEA-ME-WE series and India-Middle East-Western Europe routes pass through or terminate in Indian territory, linking major economic centres across continents. This places India at the centre of a wider network that supports global data flows, making its infrastructure important not only nationally but globally.
But Indias significance as the centre of a wider network also comes with vulnerabilities.
Also Read: The world’s in a flux. India must reform, consolidate & build a strong economy
How cable wars evolved
During World War I, Britain targeted Germany’s global submarine telegraph cable network, effectively isolating Germany from its overseas communications. These cables were part of the early international cable infrastructure often referred to as the German Atlantic cables. They linked Germany to the United States through the Emden-Azores-New York route, a crucial transatlantic line. The Emden-Vigo cable connected Germany to Spain, while German colonial cables connected Berlin to Africa and Asia.
Within days of the outbreak of war in August 1914, British forces cut five major German undersea cables in the English Channel and North Sea, effectively isolating Germany from its overseas communication network. These cables carried critical state and commercial communications, making them strategic assets. They were responsible for diplomatic messages and instructions between Berlin and its embassies worldwide, including negotiations, alliances, and wartime directives such as the Zimmermann Telegram.
Military communication orders, naval coordination with overseas forces, intelligence updates, and the movement of ships and troops all relied on cable networks. In essence, these cables carried the entire nervous system of the German state abroad, including diplomatic, military, and economic information, making their disruption a decisive strategic blow.
By the Cold War, the logic had shifted. Rather than destroying cables, major powers sought to access them quietly. Covert missions demonstrated that the true value of these networks lay in the intelligence they carried. The contest moved from disruption to surveillance, from cutting lines to tapping them.
America’s Operation Ivy Bells was one of the most daring undersea intelligence operations of the Cold War. Soviet underwater communication lines connecting key naval bases, including those overseeing nuclear submarine operations in the Sea of Okhotsk, were quietly tapped. The submarine USS Halibut located the cable, after which divers installed a listening device around it without severing the line. What followed was a steady flow of unencrypted Soviet military communications, naval movements, submarine deployments, and strategic deliberations, all captured without detection. This was a decisive shift—cables were no longer targets to be cut, but assets to be exploited.
More recently in the post-2000 world, undersea cables have taken on even greater significance, carrying vast volumes of data that sustain finance, governance, and everyday communication. As a result, competition has expanded beyond wartime tactics to include control over infrastructure itself.
States and corporations alike are investing in cable systems, shipping routes, landing points, and supply chains in ways that reflect broader strategic interests. The question is no longer just who can access information, but who can build and control the pathways through which it flows.
Also Read: China’s Motuo dam is coming. Assam has no buffer and no real-time data
A security imperative for India
What makes undersea cables especially attractive in this environment is their ambiguity. They are difficult to monitor across vast ocean spaces, challenging to repair quickly, and often lack clear attribution when damaged. This creates opportunities for actors to interfere with them without triggering direct escalation. In a world where economies and security systems depend on uninterrupted data flows, such disruptions can have consequences that far exceed their physical scale.
There have already been signs of trouble.
In September 2025, major cable disruptions took place across India, Pakistan, and West Asia. This followed the February 2024 incident in which three main cables, AAE-1, SEACOM, and EIG, were cut, with one taking five months to repair because of regional dangers. The temporary damage slowed financial systems, disrupted communications, and imposed considerable economic costs across the region. It was alleged that Houthi militants were responsible for some of these attacks.
The presence of Chinese vessels in the Indian Ocean is another matter of concern. As of July 2025, an increase in the frequency of Chinese vessels suspected of being spy ships had been noted. A 16-day maritime surveillance study by Unseenlabs in 2025 heightened concerns in the Bay of Bengal. Using radio-frequency detection, it identified nearly 1,900 vessels, with about 10 per cent displaying suspicious behaviour such as switching off AIS tracking. Some vessels were detected within 120 nautical miles of India’s coast, with indications of seabed mapping and underwater reconnaissance. The repeated presence of Chinese ‘research’ ships suggests a sustained effort to gather critical maritime data.
Consequently, India must treat undersea cables as critical national infrastructure, with resilience built through a layered security approach.
The first priority is route diversification to reduce pressure on key landing points such as Mumbai and Chennai. Equally important is strengthening indigenous repair and maintenance capabilities to ensure faster recovery from disruptions. Cable routes must also be integrated into maritime domain awareness, enabling the Navy and Coast Guard to monitor suspicious activity in real time. At the same time, landing stations require robust physical security, as well as cyber security, to prevent targeted attacks.
Regionally, India must lead co-operation in the Bay of Bengal by strengthening intelligence-sharing networks and joint response frameworks. This must be backed by a national policy that brings together all stakeholders, including telecom and maritime agencies, founded on the understanding that securing undersea cables is no longer merely a technical necessity, but a national security imperative.
Rami Niranjan Desai is a Distinguished Fellow at the India Foundation, New Delhi. She tweets @ramindesai. Views are personal.
(Edited by Asavari Singh)