The binding of isolated oxygen atoms to small tantalum clusters is investigated using vibrational spectroscopy. Infrared spectra of TanO0,1,2+ (n = 6-11) are reported in the range of 90-1100 cm(-1), comprising both the internal cluster modes and the adatom's vibrations. The vibrational spectra are compared to the results of DFT calculations for n = 6-8, which show that the oxygen atoms bind preferentially as 2-fold bridging adatoms. Addition of one or two O atoms induces only minor distortions of the underlying metal cluster core.