A robotic submersible includes a housing having a body and a tail. In another aspect, a pump and a pump tank adjust the buoyancy of a submersible housing. In a further aspect, a first linear actuator controls the pump and/or a buoyancy, and/or a second linear actuator controls a position of a battery and/or adjusts a center of gravity. Another aspect includes a pump and at least one linear actuator that control gliding movements of the housing. In still a further aspect, a motor couples a tail with a body, such that the motor controls the movements of the tail to create a swimming movement. Moreover, an additional aspect provides a controller selectively operating the pump, first actuator, second actuator, and motor to control when swimming and gliding movements occur.