Flow field is an important parameter for polymer electrolyte membrane fuel cell (PEMFC) performance to have an effect on the reactant supply, heat and water diffusion, and contact resistance. In this study, PEMFC performance was investigated using Cu foam flow field at the cathode of 25 cm2 unit cell. Polarization curve and electrochemical impedance spectroscopy were performed at different pressure and relative humidity conditions. The Cu foam showed lower cell performance than that of serpentine type due to its high ohmic resistance, but lower activation and concentration loss due to the even reactant distribution of porous structure. Cu foam has the advantage of effective water transport because of its hydrophobicity. However, it showed low membrane hydration at low humidity condition. The metal foam flow field could improve fuel cell performance with a uniform pressure distribution and effective water management, so future research on the properties of metal foam should be conducted to reduce electrical resistance of bipolar plate.