The diffusion of water in SAPO-34 was investigated experimentally in the temperature and loading range relevant for adsorptive heat transformation applications. Corrected diffusivities, which were determined by IR microscopy using adsorptive layers on aluminum supported SAPO-34 during adsorption and desorption and self-diffusion coefficients derived from NMR diffusion studies in thermodynamic equilibrium are found to be consistent to each other. They are both independent of water loading and about two orders of magnitude smaller than the diffusivity of liquid water at the same temperature. The temperature dependence of the water diffusion may be well described by an activation energy of (11 +/- 2)kJmol(-1).