Indium doped zinc oxide, ZnO(In), is a promising scintillation material for nanosecond-fast beam monitoring and counting heavy ions of MeV energy and above. We investigated the ionoluminescence and UV/Vis light transmission spectra that occur in ZnO(In) ceramic exposed to 4.8 MeV/u 48Ca and 197Au ions up to 5×1012 and 2×1011ions/cm2, respectively. Ionoluminescence and UV/Vis light transmission spectra were measured online as a function of fluence. Ionoluminescence is characterized by an intensive single emission band at 387 nm due to near-band-edge emission. We observed that the loss of the ionoluminescence intensity is more sensitive to the ion-beam-induced radiation damage than the loss of the optical transmission. The ionoluminescence intensity reduction as a function of ion fluence is described within the Birks–Black model. ZnO(In) exhibits higher radiation hardness and, thus, a longer lifetime than plastic scintillators used so far for fast-counting applications.