Optical underwater wireless communication (UWOC) uses light—typically in the blue‑green range—to transmit data through water. These systems can offer high bandwidth, low latency and good security because they rely on line‑of‑sight between transmitter and receiver, and are less prone to eavesdropping than many RF systems. They can also be compact, energy‑efficient and relatively low cost compared to acoustic and RF alternatives.

However, the survey highlights that UWOC is highly sensitive to water turbidity, scattering, turbulence and misalignment. Fluctuations in the water column can reduce range, cause short disconnections and create multipath effects that degrade signal quality, making precise alignment and tracking mechanisms necessary and limiting effective range.

For UnderSec, optical links are promising for high‑rate communication over short distances—for example between underwater platforms, sensors or inspection vehicles near critical infrastructure—provided they are integrated with other technologies that can maintain connectivity when conditions are less favourable.