Poor proton conduction at low relative humidity (RH) remains a challenge for adopting hydrocarbon (HC) membranes for polymer electrolyte membrane fuel cells (PEMFCs). Here, we report a silica-embedded hydrogel (HG-silica) nanofiller as a water reservoir for improving the performance of the HC membrane under low RH conditions. The incorporation of HG-silica into a sulfonated poly(arylene ether ketone) (SPAEK) membrane increases the proton conductivity at a low RH by an order of magnitude. The power performance under low RH conditions is also improved with the addition of HG-silica to the SPAEK membrane. Therefore, a properlystructured hydrogel nanofiller can provide a way to improve the PEMFC performance under low RH conditions.