How are undersea internet cables protected from sharks and whales? Who is responsible for keeping the world’s internet network safe?

Global internet connectivity depends on a vast network of undersea fibre optic cables that carry nearly all international internet traffic. Although these cables lie deep beneath the oceans, they are constantly exposed to natural hazards, marine life and human activities. To ensure uninterrupted communication across continents, engineers have developed multiple layers of protection that keep these cables safe from sharks, whales, anchors and harsh underwater conditions.

What are undersea internet cables?

Undersea internet cables, also known as submarine fibre optic cables, form the backbone of the global internet. Instead of relying on satellites, almost all international data including emails, video calls, banking transactions and streaming services travels through these cables laid across the ocean floor.

Each cable contains extremely thin fibre optic strands, about the width of a human hair, through which data moves as pulses of light at extremely high speeds. Despite carrying delicate glass fibres, the cables are built with several protective layers that allow them to withstand enormous underwater pressure, saltwater corrosion and changing ocean conditions for decades.

How are cables protected from sharks and whales?

One of the biggest myths about submarine cables is that sharks frequently destroy them. While shark bites have occasionally been recorded, such incidents are very rare today because modern cables are designed with strong protective coverings.

The outer section of each cable is reinforced with layers of steel wire armour and covered with waterproof polyethylene insulation. This heavy-duty design prevents shark teeth from reaching the sensitive fibre optic core. Experts believe some sharks are attracted to weak electromagnetic fields generated around cables, but the reinforced armour makes it extremely difficult for them to cause any serious damage.

Whales are generally not considered a major threat. Modern cable routes are carefully planned to avoid important marine habitats, reducing the possibility of large marine animals disturbing the infrastructure.

How are cables protected from ships and other risks?

In shallow coastal waters, human activity poses a much greater danger than marine animals. Large ship anchors, fishing nets and dredging operations can accidentally damage cables if they remain exposed.

To prevent this, specialised robotic ploughs bury submarine cables about one to three metres beneath the seabed near coastlines. In deeper parts of the ocean, where shipping activity is minimal, the cables are placed directly on the seabed because the risk of damage is significantly lower.

Before any cable is installed, engineers conduct detailed seabed surveys using sonar systems and remotely operated underwater vehicles (ROVs). These surveys help identify safe routes that avoid underwater volcanoes, sharp rock formations and environmentally sensitive marine ecosystems.

Who is responsible for maintaining these cables?

The responsibility for maintaining the global submarine cable network lies with major telecommunications companies, technology firms and international cable operators. Companies such as Google, Meta and Tata Communications invest heavily in building and maintaining these networks, while organisations like the International Cable Protection Committee (ICPC) help promote best practices for cable protection worldwide.

If a cable is damaged by an earthquake, fishing activity or another accident, specialised cable repair ships are immediately dispatched. These vessels locate the damaged section on the seabed, retrieve it using advanced underwater equipment, repair or replace the affected segment, and carefully relay the cable back onto the ocean floor.

Thanks to advanced engineering, careful planning and continuous monitoring, the world’s undersea cable network remains one of the most reliable pieces of global infrastructure, ensuring billions of people stay connected every day despite the challenging conditions beneath the oceans.