We study vortex pinning and creep in type-II superconductors produced by a low density of strong defects. Extending the strong pinning theory to account for thermal effects, we calculate the current-voltage characteristic and thus provide the first quantitative treatment of vortex creep. We describe the thermally activated flux flow regime found at small driving currents, which is characterized by constant barrier. At large drives, we find a nearly-linear regime with thermally renormalized depinning current.