In the title compound, C(14)H(12)FNO(4)S, the dihedral angle between the aromatic rings is 50.26 (9)° and the C-S-N-C bond adopts a gauche conformation [torsion angle = -68.12 (15)°]. The dihydro-dioxine ring is disordered over two orientations, which both approximate to half-chairs, in a 0.880 (7):0.120 (7) ratio. In the crystal, N-H⋯O hydrogen bonds link the mol-ecules into C(4) chains propagating in [100]. Weak C-H⋯O and C-H⋯F inter-actions consolidate the packing.