A sports boot comprising an outer shell and an inner boot, with at least one opening in the outer shell and at least one projection on the inner boot assigned to each opening, where the opening(s) and the projection(s) serve to produce a positive fit connection between the inner boot and the outer shell. The outside of the inner boot is optionally made waterproof such that no water enters the inside of the inner boot, despite the presence of the openings in the outer shell.