OPINION | Subsea telecom cables: World’s new Achilles’ heel?

The Iran war has become a nursery for asymmetric warfare and newer ways of warfighting. Iran, a regional military power dwarfed by the economic, military and diplomatic might of the US, has defied the pre-eminent superpower for nearly eight months. The war is now in an ‘election intermission’. President Trump’s “no fresh strikes before the 3 November midterms” is holding.

There is, however, no sign of a conflict closure. Even Trump’s “mother of all bombs” threat has failed to scare the IRGC. Instead, the underdog keeps coming up with innovative counter-threats and randomly prodding the soft underbelly of America’s allies in the region. Iran is also making sure the world feels the pain through energy shortages and economic damage and has successfully spread its ‘war pain’ across the globe.

The timing could hardly be worse for the oil-rich Gulf economies.  They were accelerating efforts to diversify beyond hydrocarbons by pouring billions into technology, wooing global tech firms and aspiring to become major technology and AI hubs. Data centres and subsea cables sit at the core of this push.  Microsoft’s recent announcement of a $10 billion investment in the Gulf by 2030 is part of this initiative. The plan includes $400 million for subsea and terrestrial connectivity.

Iran war has exposed how vulnerable and how unprepared the region is to geopolitical shocks. Their plan to diversify beyond oil has handed Iran levers to pressure Washington to back off. In early March, Iranian drones hit two Amazon Web Services data centres in the UAE and a third in Bahrain. Iran also claimed hitting an Oracle data Centre in Dubai. Iran’s Parliament Speaker has warned that if the US attacked Iran’s power plants and other infrastructure, vital infrastructure across the Gulf would become legitimate targets for Iran. The state media issued a statement that American companies will be targeted. Yadollah Javani, the IRGC’s deputy head of political affairs, expanded the threat further by recently announcing that the internet cables beneath the Strait of Hormuz are also on Iran’s target list.

Subsea cables converge near maritime chokepoints as they traverse the globe. In terms of numbers, the English Channel leads the list with 44 cables passing through it, followed by the US East Coast shelf and the Strait of Sicily with 32 each, and the Strait of Malacca with 29. The Red Sea and the waters around Taiwan have 17 apiece, and Suez 13. Cutting just 15 cables in the English Channel or off the US East Coast has the potential to disrupt 20 to 25 per cent of global data flows.

Hormuz is a vital artery for the Gulf countries, but is not a passage for the Europe–Asia systems. Damage from cuts in Hormuz cables may thus remain largely regional. But in the case of the Red Sea, major Europe–Asia systems run through it. This presents the Iran-backed Houthis, who retain the ability to operate around Bab-el-Mandeb, a set of attractive targets to strike. A warning came in September 2025 when the SMW4 ( South East Asia-Middle East-Western Europe 4) and IMEWE ( India-Middle East - Western Europe) cables were cut near Jeddah. This caused performance degradation in internet services to South Asia, West Asia and parts of Europe. The cause of the cable severance remained suspicious. This signalled the capability of the players involved and the distinct possibility of a serious cable disruption in the Red Sea, if Iran is pushed against the wall.

Satellites hog the limelight when we think of instant data and global high-speed internet. In reality, the unsung hero of the piece is the fibre-optic cables on the seabed. Cables carry upwards of 95 per cent of global data traffic, and by some assessments 99 per cent of intercontinental traffic; satellites account for well under 1 per cent. These cables are the backbone of the internet, telecommunications, virtual meetings, bank transactions and well over ten billion emails every hour.

The gap in data transmission speed is even more striking. NASA, some time back, claimed achieving 200 gbps, the fastest satellite data transfer achieved. Compared to this, the transatlantic MAREA cable, between Virginia Beach and Bilbao, can transmit data at about 200 terabits per second across eight fibre pairs (1 terabit = 1,000 gigabits).

Trans-ocean telecom cables have a long history.  The earliest attempts to lay subsea cables were made in the 1840’s. The first successful transmission using subsea cable was an 1858 trans Atlantic transmission. The mission, however, lasted only a few hundred messages over a few weeks, due to cable damage. By 1866, a functional cable was successfully installed across the Atlantic Ocean. Cables improved over the years, and the first fibre-optic undersea cable was laid between the US, the UK and France in 1988.

Today, over 600 systems are in service, stretching some 1.5 million kilometres. Another 100 are planned. Major new cable systems are the Juno system (Japan–California, about 10,000 km, 350 Tbps), Amazon’s Fastnet (US–Ireland, over 320 Tbps) due in 2028, and Meta’s Petal (US–France, about 7,000 km), billed as the first petabit-class cable, capable of one million Gbps, due in 2029.

India is in the middle of its own cable rush. Reliance Jio’s twin systems, IAX and IEX (India-Asia Xpress and India-Europe Xpress), together span over 16,000 km with more than 200 Tbps capacity, and are expected to be commissioned soon. MIST (Myanmar/Malaysia-India-Singapore Transit), about 8,100 km, Mumbai-Chennai to Singapore, is nearing launch. Bharti Airtel, invested in 34 international cables, holds about 20% of the 19,200-km SEA-ME-WE 6 (Southeast Asia–Middle East–Western Europe), which runs from Singapore to France via Egypt and is due in service in 2026. Google’s America-India Connect, with a new gateway at Visakhapatnam, is in the pipeline, while Microsoft, Tata Communications, Singtel and Lightstorm are building I-2SEA (India–South East Asia), targeted for the end of 2029.

Subsea cable deployment involves high capital investment.  The complex marine environment calls for special customised cable laying vessels and equipment as well as specialised technology & skills. These vessels need unique onboard systems like the Dynamic Positioning systems that hold the cable-laying ship on precise navigation coordinates, the Linear cable engines that continuously monitor cable tension and feed the delicate fibre optic cable and the Subsea ploughs which operate remotely. Redundancy is a standard design feature of subsea network architecture.

The underwater environment is harsh. Apart from normal wear & tear, earthquakes, landslides, fishing and anchor drags pose maintenance challenges. Deliberate acts of war have also entered this list now. Submarine fibre-optic cables are generally designed for a 25-year life. Globally, there are about 150 to 200 subsea telecom cable faults a year. About 70 to 80 per cent of them come from fishing gear and ship anchors in shallow waters, and are repaired quickly. Natural hazards account for less than 10 per cent, but can be devastating. In 2020, Congo River floods triggered a sediment-laden underwater avalanche in a deep-sea canyon off West Africa and severed two major cables.

The repair fleet is a real bottleneck. There are only about 60 subsea cable laying / maintenance ships worldwide. About half of this fleet will reach the end of its service life by 2040. An ageing fleet, surge in demand, limited number of specialist carrier manufacturers and preference for building high-margin LNG carriers are some of the challenges faced by the subsea cable industry.

Politics adds its own friction. Laying a subsea cable needs regulatory approval from every coastal state whose territorial waters or Exclusive Economic Zone it crosses, each with its own clearance authorities and timelines. UNCLOS guarantees the freedom to lay cables on the high seas and in EEZs, yet cable companies regularly face fee demands on assorted counts, delays in approvals and security-driven restrictions in disputed waters like the South China Sea.

The world is getting irrevocably integrated, digitally. Statista expects global data generation to triple between 2025 and 2029 – roughly 30 per cent growth a year. Amid this data tsunami, a quieter and equally significant change is under way in who owns the cables. Until the 1990s, subsea cables were typically built by consortia of national telecom carriers such as AT&T, British Telecom, Telstra etc. Lately, the content and cloud giants–Google, Meta, Microsoft and Amazon–have become the leading investors, often building private cables on their own or with a few partners. TeleGeography data show them as stakeholders in over two-thirds of the systems now being planned. A 2026 National Bureau of Economic Research paper estimates that 70 per cent of global data flows today traverse at least one US-owned cable somewhere along the route, up from under 20 per cent in the early 1990s.

Deliberate disruption of subsea cable systems by adversaries or even non-state actors is a real threat. This, combined with concentrated corporate control, vulnerable chokepoints and the relative ease of severing these cables, makes our digital future slippery and inadequately secure.

Are the subsea telecom cables becoming the world’s new Achilles’ heel?

(The opinions expressed in this article are those of the author and do not purport to reflect the opinions or views of THE WEEK)