Underwater capabilities are maritime and subsurface capabilities used for sensing, protecting, disrupting, or maintaining activity below the surface. They can include seabed sensors, underwater communication links, unmanned vehicles, mine warfare systems, and protection of subsea infrastructure such as cables, pipelines, and ports.
In cyber security and national security, this term matters because the underwater domain is both physical and data-driven. Many critical systems depend on buried or submerged assets that are hard to inspect and even harder to replace quickly. Attackers may try to map, tap, jam, or damage these systems, while defenders use monitoring, redundancy, encryption, and anomaly detection to keep them reliable. Underwater capabilities therefore sit at the intersection of defense operations, infrastructure security, and resilience planning.