The first photoelectrochemical study of semiconducting YH3 - x films formed by etching bulk Y metal in 0.5 M H2SO4 solution is reported. The formation of semiconducting hydride having an indirect optical band gap, E-g(opt), of about 2.35 eV is confirmed by in situ photocurrent spectroscopy. The photoelectrochemical behaviour of such a phase was investigated both in alkaline and in acidic solutions. The flat band potential was estimated to be U-fb = - 1.25 V/NHE, independent of pH.