Abstract: A fuel cell system comprises at least one fuel cell having an air inlet and an exhaust gas outlet, an air supply device connectable to the air inlet and an exhaust gas extracting device connectable to the exhaust gas outlet. Further, a water extraction device has at least two drying units, wherein the water extraction device is adapted for selectively providing a fluid connection from the air supply device to the air inlet of the fuel cell be means of one of the at least two drying units and from the exhaust gas extracting device to the exhaust gas outlet by means of another one of the at least two drying units. Thereby, an optimal drying process is conducted that does not influence a dynamic power generation.