An submersible desalination unit composed of a structure containing a water intake system for acquiring sea water, a sea water pre-filtration system for removing lager contaminants and debris, a reverse osmosis system for the purification of the water, a permeate transfer system to carry the water to where it will be used, a power source for powering the equipment used in the process and a control system that operates and monitors the equipment and process of removing salt from the water and transferring the desalinated water to other use and returning the brine solution to the sea.