This chapter is aimed at affording the basic aspects of such topic from a control perspective. After a brief Introduction, Modeling is discussed in terms of reference systems, kinematics and dynamics of rigid bodies moving in a fluid. The sensory and actuating suites available for underwater vehicles are discussed next. Underwater robotics within the classical control architecture of navigation, guidance and control is finally considered with basic numerical exercises to better understand the specifics of such systems. A small introduction to underwater intervention concludes the chapter.