We study the Cauchy Problem for the relativistic Boltzmann equation with near Vacuum initial data. Unique global in time mild solutions are obtained uniformly in the speed of light parameter c ≥ 1. We furthermore prove that solutions to the relativistic Boltzmann equation converge to solutions of the Newtonian Boltzmann equation in the limit as c → ∞ on arbitrary time intervals [0, T ], with convergence rate 1/c 2−ǫ for any ǫ ∈ (0, 2). This may be the first proof of unique global in time validity of the Newtonian limit for a Kinetic equation.