1.5 million km of cables on the ocean floor need protection and defense

Economies and societies, continents and countries, cities and ports are connected by nearly 1.5 million kilometers of fiber-optic cables laid on the ocean floor. Today, electrical cables and oil and gas pipelines are not the most important lifeblood ensuring the functioning of the global world. The most important and sensitive is the global nervous system, through which 99% of data flows.

These submarine fiber-optic networks, stretching 1.5 million kilometers, ensure everyday communication between people, according to Phil Gervasi, Director of Tech Evangelism, on the Kantik blog. They ensure collaboration between business partners and the exchange of information between financial and scientific institutions. Undersea cables facilitate the operation of hospitals and medical services, ensure the defense and protection of states, and ensure the functioning of entire continents. Without the web of ocean cables, even local internet use, international organizations, and governments would be impossible.

According to estimates, by early 2025, over 1.48 million kilometers of submarine cables were in operation worldwide. Some cables are short, such as the 131-kilometer CeltixConnect cable between Ireland and the United Kingdom. Others are very long, such as the 20,000-kilometer Asia America Gateway cable. As of early 2025, more than 600 active and planned submarine cables were in operation, reports TeleGeography.

Shetland Without Cable

At the end of July 2025, many residents of Shetland and Orkney lost their internet connection, and businesses and government offices shut down. Islanders have been without internet access since the SHEFA-2 cable failed on Saturday, July 26, when a fishing boat likely damaged the connection near Orkney. A much more serious outage occurred in 2022.

“Shetland News” reported on the case of a post office in Lerwick, which had to close due to a lack of internet and the inability to use 4G mobile data as a backup connection. The SHEFA-2 cable has several connections – one between the Faroe Islands and Shetland, and another from Shetland to Orkney. There is another cable from Orkney to mainland Scotland. As a result, some internet providers were able to reroute calls from Shetland to the Faroe Islands after the outage, the BBC reported.

The events in the Baltic Sea in 2024 and 2025 have exposed the weaknesses of our global submarine cable infrastructure. In the face of ongoing geopolitical tensions, cooperation between nations and industries is essential to invest in robust protective measures and develop technologies to secure these crucial communication lines.

The capacity of these cables far exceeds that of satellites, offering data transmission speeds of terabits per second, compared to the typical 1 gigabit per second for satellites, emphasizes Carlos Corrêa, International Network Engineer – Optical Transport Engineer at Maivix Technology. “This dramatic difference highlights the dependence of our digital infrastructure on these underwater systems.”

“Beyond personal and commercial use, submarine cables are integral to national security, supporting military operations and intelligence communications. Their uninterrupted operation is crucial; any disruption could lead to significant economic and security challenges,” explains Carlos Corrêa.

The importance of subsea connectivity has grown significantly during and after the COVID-19 pandemic, fueled by growing demand for high-speed connectivity, fueled by advances in artificial intelligence, financial flows, cloud computing, and the development of IoT-enabled logistics.

Security and Resilience

Ensuring the security and resilience of communications systems has become more important than maintaining the continuity of supply chains. High-speed connectivity enables the flexibility of global logistics networks. The security of underwater fiber-optic cables is crucial for maintaining efficient administration, governance, and management. All these processes require the seamless flow of information that underpins the functioning of modern society.

“If you send an email, activate artificial intelligence, or book a flight, there’s a high probability that your request will be transmitted via a fiber-optic submarine data cable,” writes Christian Bueger, a professor at the University of Copenhagen, a research fellow at the United Nations Institute for Disarmament Research (UNIDIR), and the author of the book “Understanding Maritime Security,” on his blog.

A significant portion of IT and information operations utilize terrestrial, or rather, underground, networks. However, when a service or data center is being performed on another continent, the maritime network is used. Bueger estimates that “Nearly 1.5 million kilometers of submarine fiber-optic cables—comprising over 400 active systems—lie hidden on the ocean floor.”

And here, of course, the question arises whether the cables lying on the seabed are actually hidden. Information flows continuously, in the form of bits and bytes, between computer centers, laptops, and 6 billion smartphones.

Broken Cables

They say “accidents happen to people.” But that’s not all. Undersea cables do too. Like other infrastructure systems, cables are also susceptible to damage. Bueger claims that “Undersea cables break constantly – on average, two to four breaks occur somewhere in the world every week, and 86% of cable failures are due to fishing-related and anchoring-related failures.” Most network operators implement redundancy to prevent service interruptions, and in most cases, such failures go unnoticed.

“If you live in a remote location like an island, it might be different,” warns Bueger. For example, in October 2022, two cables connecting the Shetland Islands, located 160 kilometers off the northern coast of Scotland, were severed. The undersea telecommunications cable connecting Shetland, Orkney, and the Faroe Islands with mainland Scotland was damaged, causing internet and telephone service disruptions.

“The damage occurred approximately nine kilometers off the coast of Orkney. It was suspected that the cable had damaged a fishing vessel,” reported the Shetland News. The cable break left 23,000 residents without communication. Additional emergency services were dispatched to the islands. No mention was made of the consequences for protecting the territory and waters surrounding the islands.

The above-mentioned case is just one of many incidents involving cable damage. It is emphasized that ensuring rapid repair, resilience, and system redundancy is important. This must also be taken into account when building the energy transmission system and the control system for offshore wind farms.

For some time now, we have been looking at cases of communication breakdowns via submarine cables from a different perspective. It is increasingly common to find that cables are deliberately damaged. The most striking examples were observed in the Baltic Sea. These incidents coincided with tensions in international relations following the Russian invasion of Ukraine and the escalation of tensions between Russia and NATO. Pipelines and several cable connections were damaged.

“Although it has not been possible to fully determine whether these incidents were the result of poor seamanship or deliberate sabotage, they clearly revealed the vulnerability of cable systems to attacks,” emphasizes Professor Bueger.

Źródło: Straits Research

Strategic Recommendations

Following the COVID-19 pandemic, the submarine cable market is experiencing significant growth, driven by rising global demand for data and technological advancements. The global submarine cable market was valued at approximately $29.94 billion in 2024 and is projected to reach $49.31 billion by 2033, growing at a compound annual growth rate (CAGR) of 5.7% during the forecast period, according to the “Submarine Cables Market Size” market report, prepared by Straith Research experts.

The Center for Strategic and International Studies (CSIS) report, “Safeguarding Subsea Cables: Protecting Cyber ​​Infrastructure amid Great Power Competition,” by Daniel F. Runde, Erina L. Murphy, and Thomas Bryj, highlights the importance of increasing the resilience of submarine cable systems. Key recommendations include:

• Increasing redundancy: Laying additional cables with higher capacity to provide alternative data transmission paths in the event of disruptions.

• Improving recovery capabilities: Increasing the ability to quickly maintain and repair cable systems to minimize downtime.

• Strengthening supply chains: Recognizing the global nature of the cable component supply chain, ensuring secure and reliable sources of key parts.

The dynamic market growth is driven by growing demand for high-speed internet and efficient data transmission, as well as significant investments in the construction of new submarine cables. Operators are considering alternative connections to the Asia-Pacific region to bypass the disputed waters of the South China Sea.

Taiwan is a geopolitical hotspot prone to frequent cable downfalls. Over 20 such incidents have been reported in recent years, notes Robert Clark, editor of “Light Reading.” New cables are being laid to bypass disputed waters and create new intercontinental connections that take into account the strategic resilience of communications systems.

Investment in the fiber-optic cable market in the Asia-Pacific region alone is expected to grow from $6.45 billion in 2023 to $16 billion in 2032. This growth is driven by numerous factors, including the development of 5G networks.