The native oxides formation on ambient-stored metalorganic vapour phase epitaxy (MOVPE) grown GaAs, InP and InAs is documented by contact angle measurements and X-ray photoelectron spectroscopy (XPS). The time dependent transitions from hydrophobic to hydrophilic states are presented alongside the change in relative amount of different types of oxides forming on the epitaxial surfaces. We present a qualitative agreement of wettability properties with the amount of group III oxides and lack of such correlation with the overall oxide composition, somehow indicating a (surprising) minor role of group V oxides. © 2014 IEEE.