Catalyzes the hydrolytic dehalogenation of small (R)-2-haloalkanoic acids to yield the corresponding (S)-2-hydroxyalkanoic acids. Acts on acids of short chain lengths, C(2) to C(4), with inversion of configuration at C-2. an (R)-2-haloacid + H2O = a (2S)-2-hydroxycarboxylate + a halide anion + H(+) Homotetramer. Belongs to the HAD-like hydrolase superfamily. S-2-haloalkanoic acid dehalogenase family.