The field of underwater robotic is under development and most products are not yet commercially established. There are very few available devices that can perform tasks autonomously on the basis of information provided by a series of sensors and they are generally designed for specific uses. In recent years, due to the constant reduction of production costs and the availability of a range of new sensors, applications of robotics are expanding into non-traditional sectors. Underwater activities definitely represent a field where there is considerable need for autonomous vehicles but, at the same time, one of the most challenging, because of the difficulty to exploit the solutions used in earth robotics. This implies that the technological solutions, as well as the mathematical models, used for underwater robots are still under study and research, and certainly represent an area requiring a significant effort in terms of investments.