The influence of different dopants on the hydrogen dynamics in the high-temperature protonic conductor based on strontium cerate was investigated by means of neutron vibrational spectroscopy. The differences in the vibrational spectra up to an energy transfer of 130 meV are discussed. The results indicate the presence of a considerable amount of hydrogen associated with the dopant. The corresponding OH vibrational modes were found to depend strongly on the radius of the dopant cation. Moreover, a temperature study revealed a delocalization of the dopant-related hydrogen near 200 K and above.