The aim of this study is to design and implement an inductive wireless charging system for underwater autonomous vehicles, capable of maintaining stable and controllable output voltage and current despite variations in the distance and angle between coils. The system utilizes an S-S compensation structure to minimize reactive power consumption. In this configuration, changes in mutual inductance do not affect the power factor, although they alter the output current magnitude. Since the system operates underwater, wireless data transmission for feedback of current or voltage between the primary and secondary coils would be overly costly. Therefore, to eliminate the need for wireless data communication, a secondary-side DC-DC converter is employed to control voltage, current, and maintain constant output power. Additionally, to reduce battery charging time, a constant-power constant-voltage (CP-CV) charging method is adopted. In system simulations, the effect of DC-DC converter pulse width variation on input power factor was analyzed, revealing that by limiting the inverter pulse width to a 0–50% range, its impact is minimized. Experimental results demonstrate that, with coil distance and angle variations from 1 to 13 cm along the x, y, and z axes, and coil angle variations from 0 to 45 degrees, the system’s output voltage and current remain completely stable. To establish the permissible range for coil displacement and misalignment, if minimum system efficiency is set at 50%, the maximum allowable distance is 7 cm along the x-axis (perpendicular to the coils), 11 cm along the y and z axes, and the maximum allowable angle is 22 degrees. These findings are confirmed through practical experiments.