Over 99% of all international data is transmitted through cables on the ocean floor.

The global subsea cable network consists of over 550 active and planned cables stretching more than 1.4 million kilometers. This infrastructure is managed by organizations like TeleGeography, which tracks the growth of these critical links. While satellites are essential for remote areas, they cannot match the speed or bandwidth of fiber optics. Fiber-optic technology uses thin strands of glass to transmit data as pulses of light at nearly the speed of light.The first trans-Atlantic telegraph cable was laid in 1858, but modern fiber-optic versions only became standard in the late 1980s. The TAT-8 cable, launched in 1988, was the first fiber-optic cable to cross the Atlantic Ocean. Today, these cables can carry dozens of terabits of data per second. This capacity is vital for everything from high-frequency stock trading to streaming high-definition video across continents.Maintenance of this network is a massive industrial undertaking involving specialized cable-laying ships. These vessels use submersible plows to bury cables deep into the seabed to protect them from fishing trawlers and ship anchors. Despite their importance, the cables are surprisingly thin. In deep water, where the risk of damage is lower, the cables are often only about 25 millimeters in diameter. In shallower waters, they are heavily armored with additional layers of galvanized steel wire.