Experiments were conducted to photograph the structures of high-speed conventional (CWJ), forced pulsed (FPWJ) and abrasive-entrained forced pulsed (PAWJ) waterjets. The objective was to determine the effect of operating parameters (pressure, flow, amplitude of the vibrating probe, etc.) on the structures, which influence the performance. Paint removal tests were made to compare their efficiencies. The experimental study has clearly shown that these parameters have significant influence on performance, and that PAWJ is more effective than the other two types of waterjet. © BHR Group 2006 Water Jetting.