The kinetics of water vapour sorption by several anhydrous hydrophobic and hydrophilic ionic liquids (ILs) were gravimetrically determined at 25 °C and two levels of humidity, namely 43 and 81%. A simple equation was used to fit the data. The kinetic parameters obtained from the different ILs were compared and the differences were related to the IL structures. Results showed that even hydrophobic ILs absorb water at an unexpected speed.