Water transport in polymer electrolyte membrane fuel cells (PEMFCs) is investigated by synchrotron X-ray imaging as a non-destructive testing method. Two different measurement techniques, namely in-situ radiography and quasi-in-situ tomography were combined to reveal the relationship between the structure of the microporous layer (MPL) and the water flow at different operation temperatures. It is shown how water distribution and transport are quantified and visualized. With this method, investigations of different cell materials at different operating parameters such as cell current, gas humidity, gas flow, etc. are conducted.