The conductivity of the high temperature proton conductor Ba3Ca1.18Nb1.82O9-delta has been investigated by means of impedance spectroscopy in the temperature range between ambient temperature and 1000 degrees C. Bulk, grain boundary and electrode contributions could be identified. The total resistance of the ceramic samples was found to be dominated by the grain boundary contribution which thus limits the total conductivity. The grain boundary resistance suffered from aging effects. The bulk conductivity follows an Arrhenius behavior with an activation energy of (0.55+/-0.03) eV.