Underwater communication is a technology for transmitting information in an underwater environment. These technologies face various challenges, such as signal attenuation, scattering, and reflection of signal due to seawater absorption of sound or electromagnetic waves. To overcome these challenges, several technologies have been developed including underwater acoustic, optical and electromagnetic communications, and acoustic communications. Acoustic communications offer the longest range but slowest transmission rate, it suffers to attenuations caused by salinity, temperature and pressure which are further influenced by depth of the sea. Optical communications offer high transmission rate but are limited in terms of range caused by fluctuations of the water or demand the use of optical cables. Electromagnetic communications is the least researched technology of these three, it offers numerous benefits compared to other communication types but current biggest obstacle is the high attenuation of underwater conditions. Underwater communications are most commonly used in civilian sector, scientific research, military operations and offshore oil exploration.