Fuel cell based power systems have high energy density. However, using H-2 gas as fuel and O-2 as oxidizer in aerospace, UAV or underwater like an AIP (Air Independent Propulsion) environment has restrictions in terms of efficient storage. The direct borohydride hydrogen peroxide fuel cell (DBPFC) which uses aqueous NaBH4 solution as fuel and H2O2 solution as oxidizer has great advantages over the H-2/O-2 fuel cell in terms of storage efficiency, energy density and power density. These excellent characteristics make the DBPFC an appropriate power source and propulsion system for AIP systems. In this study, lightweight magnesium bipolar plates for DBPFC has been fabricated and evaluated for application in unmanned underwater vehicles. Although magnesium has many favorable properties such as lightweight, high electric conductivity and machinability, low corrosion resistance restricted its use as a bipolar plate. Corrosion resistive metal, Au electroplated magnesium bipolar plates exhibited the highest power density and the promising candidate for future aerospace, UAV and underwater propulsion systems.