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In order to study the mechanism and parameters of hydrogen diffusion in the cubic (C15-type) Laves phase YMn 2 , we have performed quasielastic neutron scattering measurements in YMn 2 H x (x = 0.4, 0.65 and 1.26) over the temperature range 30-395 K. It is found that the diffusive motion of hydrogen in this system can be described in terms of two jump processes: the fast localized H motion with the jump rate τ −1 l and the slower process with the rate τ −1 d associated with H jumps leading to long-range diffusion. The ratio τ d /τ l at room temperature is close to 10 2 . Our results suggest that the localized H motion in YMn 2 H x corresponds to back-and-forth jumps of hydrogen atoms within pairs of interstitial g (Y 2 Mn 2 ) sites. The parameters of the long-range diffusion of hydrogen in the samples with different H content are found to be close to each other. In the range 210-395 K, the temperature dependences of τ −1 d and the hydrogen diffusivity are reasonably described by the Arrhenius law with activation energies 0.18-0.22 eV.