Flow in the initial region of a pulsating low-speed annular water jet issuing into a quiescent water reservoir was visualized by means of a dye. The objective of this study was to characterize the different flow regimes as a function of pulse frequency. The blocking ratio was fixed at 0.7. The Reynolds number was varied from 59 to 155 and the Strouhalnumber from 0.133 to 1.90. For the experimental conditions considered, two different flow regimes were observed.