Permeation experiments of ethylene were performed to investigate the effect of carrier mobility on carrier saturation in a facilitated transport membrane. Poly(vinyl alcohol)-based membranes containing either Na+-ions or Ag+-ions were used to prepare mobile-carrier and fixed-carrier membranes. For the membranes containing 0.49 M Ag+-ions, the fluxes obtained from the mobile-carrier membrane were higher than those obtained from the fixed-carrier membrane. It was also observed that the fixed-carrier membrane was more susceptible to the carrier saturation than the mobile-carrier membrane. However, the effect of carrier mobility on permeation flux and carrier saturation was not noticed as the carrier concentration was increased.