Mechanical robustness of polymer electrolyte fuel cell (PEFC) electrodes is essential to keep the performance and to improve the durability. To increase the mechanical robustness, mechanical behavior of PEFC electrodes should be investigated because the mechanical failures such as cracks, tears and punctures are critical to lifetime decrease. However, there are no attempts to investigate the mechanical behavior of a pristine electrode without any substrates because it has been a significant challenge due to its porous and brittle nature. Therefore, we present a novel method that can be used to investigate the mechanical behavior of free-standing PEFC electrodes on the water surface. The water surface enables measurement of the mechanical properties of electrodes due to its high surface tension and low viscosity. To separate the pristine electrode from the decal transfer film without damage, we adopted an innovative ice-assisted separation method. The tensile tests on water surface were conducted to understand of the effect of the ionomer content and Pt loading. Young’s modulus, elongation at break and tensile stress at break increased with increasing ionomer content in all Pt loading conditions. Also, the scaling law relationship of E~ρ^1.6 between Young’s modulus and density was suggested. Our method can be used to design mechanically robust electrode for PEFC or evaluate the degradation degree of electrodes.