Configuration-interaction wavefunctions for 3s23p2P0, 3s3p22,4P, 2D, 2S, 3s23d2D, 3p34S0, 2D0, 2P0 states are calculated for S IV and are used to calculate oscillator strengths, both length and velocity forms, and transition probabilities for transitions between these states. It is found that, for allowed transitions, use of elaborate wavefunctions is more important than relativistic corrections. Comparison with recent beam-foil experimental data is generally good.