Field experiments were conducted to investigate the near-field dilution characteristics of a hypersaline brine discharge into coastal waters via an offshore diffuser from a desalination plant. The aim was to determine the dilution of the negatively buoyant plume as it exited the diffuser under three different discharge Froude number regimes (one-third, two-thirds, and full-flow capacity) and to compare these measurements to scaling arguments derived from laboratory measurements. Equations based on the densimetric jet Froude number F , obtained from laboratory experiments, were found to adequately describe the dilution of the brine for cases when F>20 . For F<20 , no laboratory results exist and the dilution was found to be greater than that anticipated from an extrapolation of the laboratory results.