To get an insight into the mechanism of cation diffusion in stabilized zirconia. the diffusion of all stable lanthanides was measured simultaneously in zirconia stabilised with scandia (ScSZ), yttria (YSZ) and calcia (CSZ). It was possible to identify all lanthanides with SIMS and to obtain the bulk diffusion coefficients between 1400 and 2000 K from SIMS depth profiles. For CSZ and YSZ, the lanthanide bulk diffusivities increase with increasing lanthanide ionic radius, while for ScSZ, they are nearly independent of the radius. The experimental activation enthalpies and pre-exponential factors are highest for two-valent CSZ and for the three-valent systems ScSZ and YSZ. They are not strongly affected by the type of the lanthanide for all systems investigated. (C) 2004 Elsevier B.V. All rights reserved.