We report a measurement of the branching fraction and final-state asymmetry for theB 0 → K 0 S K ∓ π ± decays. The analysis is based on a data sample of 711 fb −1 collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e + e − collider. We obtain a branching fraction of (3.60 ± 0.33 ± 0.15) × 10 −6 and a final-state asymmetry of (−8.5 ± 8.9 ± 0.2)%, where the first uncertainties are statistical and the second are systematic. Hints of peaking structures are seen in the differential branching fractions measured as functions of Dalitz variables.