A charging system for an unmanned underwater vehicle (UUV) is disposed within a submerged docking station. The charging system includes a battery, a fuel cell, a fuel source, and a charge controller. The battery supplies electrical power to an electrical distribution bus in the docking station. The charge controller monitors the charge state of the battery and, when needed, activates the fuel cell to recharge the battery. The charge controller also activates the fuel cell when a UUV is docked in the docking station for recharging of its power plant.