A transatlantic communications cable is a submarine cable connecting Europe and North America across the Atlantic Ocean, carrying telecom signals. Early versions were single-wire telegraphs (like the 1858 cable), evolving to coaxial in the mid-20th century, and now optical fiber with amplifiers for high-speed data.
As of recent data, about 20 active fiber-optic cables span the Atlantic, handling 99% of international data traffic.
They're installed by telecom giants and consortia (e.g., Google, Meta, Microsoft, Tata Communications) using specialized cable-laying ships like those from SubCom or Alcatel Submarine Networks.