The diffusion of two volatile fission products, xenon (Xe) and krypton (Kr), in zirconia (ZrO₂) is investigated. Samples of Yttria (Y₂O₃)-stabilised tetragonal ZrO₂ were implanted with either Xe or Kr, at 300 keV, with a fluence of 10¹⁷ at./cm², and subsequently analysed with time-of-flight elastic recoil detection analysis (ToF-ERDA) to obtain elemental composition depth profiles. Samples were then annealed at 1200 °C for 9 h, and the effect of the annealing was assessed by ToF-ERDA measurements. From these measurements, first-order approximations of diffusion coefficients for Xe and Kr in ZrO<inf>2</inf> were derived, using a model based on Fick's second law, these being (1.36±0.87)×10⁻¹⁹ m²/s and (2.94±1.96)×10⁻¹⁹ m²/s at 1200 °C for Kr and Xe respectively. It was shown that ToF-ERDA can provide data to analyse the diffusion of elements in solid sample matrices and that a model based on Fick's Law can predict the diffusion of the implanted ions.