We report NMR experiments at 8 T on 3He and 3He-4He mixtures filling the pores of 95% porous aerogel, for temperatures T ≥ 6 mK. Magnetization measurements of pure 3He reveal a localized layer approximately one monolayer thick. The longitudinal relaxation includes a component logarithmic in time, which is apparently associated with a fraction of the localized 3He atoms. When the localized 3He is displaced by adding 4He the logarithmic relaxation disappears and T1 for the dominant exponential relaxation increases. Measurements of the spin diffusion coefficient with the aerogel filled with dilute solution in equilibrium with bulk phase-separated mixture provide an unambiguous determination of the spin mean free path, ℓs = 58 nm.