This experimental study investigates the evolution of mean flow and turbulence in the near field of an immiscible buoyant oil jet injected into water at a low Reynolds number (Re=1230). Refractive index matching of the liquid pair using silicone oil and sugar water enables simultaneous applications of particle image velocimetry and planar laser induced fluorescence. The results include flow visualizations, ensemble-averaged phase and velocity distributions, and Reynolds normal and shear stresses for each phase and combined. Trends are compared to those of a single-phase jet. Close to the nozzle, the surrounding water gains momentum when thin layers are entrained into the jet. Also, as oil ligaments begin to extend outward, water-containing vortices form around their tips. Further downstream, as the oil breaks up into blobs and then to smaller droplets, the spreading rate of the oil volume fraction and the decrease in its centerline concentration are lower than those of the axial momentum and centerline velocity. Universal profiles of either the phase distribution or the axial momentum scaled with the half widths and centerline values develop after six diameters, the latter occurring earlier than the single-phase jet. As expected, the mean velocity in the oil is higher than that in the water, and after thirteen diameters, the difference between them is consistent with the buoyant rise velocity of oil droplets with the same Sauter mean diameter in turbulent flows. Initially, the normal and shear Reynolds stress components in the oil jet are higher than those in the single-phase jet, but the differences between them decrease with axial distance. Phase-conditioned statistics in the oil jet reveal significant spatially varying discrepancies between the turbulence level in the oil and water phases. The peripheral turbulence in the water is higher near the jet exit, but lower after six diameters. The latter trend is attributed to the intermittency and lower peripheral shear-dominated turbulence production rate in the entrained water. In contrast, near the jet centerline, the turbulence production rate, hence the turbulent kinetic energy, is higher in the water. Here, while the axial contraction increases the turbulence in both phases, the radial extension in the spreading oil, as opposed to the radial contraction in the entrained water, causes a discrepancy in the production rates. After thirteen diameters, the differences between oil and water turbulence levels diminish. Still, the axial velocity fluctuations are substantially higher than the radial ones. The oil blob size distribution in this region still has a Sauter mean diameter that is five times larger than that measured after thirty diameters, indicating that fragmentation of the oil persists well beyond the range examined in this paper. © 2021 American Physical Society.