Platinum(II) and palladium(II) complexes are well-known to catalyze the partial oxidation of alkanes. Herein, we present experimental evidence that tunneling occurs in the protonolysis of M-II-CH3 (M = Pt, Pd) model systems. We propose that there may be a connection between the observation of tunneling and a protonolysis mechanism involving direct protonation of the M-C bond and that tunneling may also be expected for electrophilic C-H activation of methane by P-II and Pd-II that proceeds via direct proton loss from a sigma complex.