Integrated penetrator and proximity sensor probe assemblies are provided for monitoring a position of a rotating target within a subsea rotating device such as subsea motors and pumps. The integrated penetrator and proximity sensor probe assemblies are configured to communicate information related to the position of the rotating target through a wall of the device housing, and can be inserted through an opening in the wall of the device housing and mounted to the wall of the device to position a proximity sensor tip assembly adjacent the rotating target. The proximity sensor probe assemblies are pressure-compensated and configured to withstand subsea pressures and conditions.