Underwater acoustic communication is a technique of sending and receiving messages below water. There are several ways of employing such communication but the most common is by using hydrophones. Underwater communication is difficult due to factors such as multi-path propagation, time variations of the channel, small available bandwidth and strong signal attenuation, especially over long ranges. Compared to terrestrial communication, underwater communication has low data rates because it uses acoustic waves instead of electromagnetic waves.
At the beginning of the 20th century, some ships communicated by underwater bells, the system being competitive with the primitive Maritime radio navigation service of the time.

Global underwater acoustic communication equipment market was valued at 40.72 Million US$ in 2018 and is projected to reach 75.55 Million US$ by 2024, at a CAGR of 10.85% during the forecast period.

Research analysis on the global underwater acoustic modem market identifies the increasing adoption of underwater acoustic modems in naval defense to support communication system as one of the primary growth factors for this market. These systems are used in applications such as submarine communications; diver communications; and remote underwater monitoring, command, and control. The focus of the developed countries towards strengthening their naval defense force will increase the applications of the defense acoustic modems, which will propel the market’ growth.
During 2016, the Americas contributed to the highest revenue to this market and this was mainly due to the increased spending by the region’s defense sectors on communication services. The US is the major market for underwater acoustic modems in this region, where the growing adoption of underwater communication networks in both the marine and naval defense sectors augments the market’s growth prospects.

Key players in global underwater acoustic communication equipment market include: DSPComm, EvoLogics, LinkQuest, Teledyne Benthos, L3 Oceania, Nortek AS, AquaSeNT, Sonardyne, Underwater Technologies Center etc.