Wireless underwater communication is a very challenging task. The most commonly used methods for wireless communication in the air, do not work in the water. There are three types of underwater communication in literature. These are Radio Frequency (RF), Acoustic and Optical communication. 

Radio Frequency based underwater communications held on VLF (Very Low Frequency) and ELF (Extremely Low Frequency) radio waves. In both frequencies, underwater RF communication system requires large sized antennas and it consumes high energy when it’s compared with other methods. Also RF communication emits radio waves, which can be detected or intercepted by other underwater measurement systems with antennas. Therefore, underwater RF communication is not feasible for implementation. For acoustic based underwater communication, acoustic modems are used. The speed of the acoustic waves in the water is much greater than the acoustic waves in the air, and acoustic modem communication signals can also be detected or intercepted by an underwater measurement system with a hydrophone. When we compare underwater communication systems, optical communication has more energy efficiency, more communication channels and is more secure than RF and acoustic underwater communication systems. Therefore optical communication is the best option for underwater communication.