Recent interest in hydrogen technologies has led to many questions, including how to store hydrogen. Some fields, such as aeronautics, are considering storing hydrogen in the liquid state, i.e. at cryogenic conditions (T<120K) and atmospheric pressure. Polymers and composite materials are good candidates for these storage tanks (high mechanical performance/weight ratio), but the phenomena of gas transport at these temperatures are still poorly understood. This study therefore aimed to characterize the permeability, diffusion and solubility of polymers materials at cryogenic temperatures. A specific experimental permeability test setup was developed for this purpose, which temperature can be controlled down to 55K (-220°C). This original device was used to study the effect of glass transition and crystallinity of semi-crystalline thermoplastic materials on permeability temperature-dependence. The results show that the glass transition reduces the barrier effect of PVDF, while the crystallinity improves PEKK impermeability at low temperature. Comparison of these two polymer families shows that PVDF has an excellent helium impermeability property that is better than PEKK’s.