This experimental study investigates the impact of two diametrically positioned sonic air tabs on the mixing characteristics of a Mach 2.1 circular jet. Positioned at an axial distance of 0.25D from the convergent-divergent nozzle exit, the air tabs’ injection pressure ratio was systematically varied from 3 to 6, while maintaining nozzle pressure ratios of 3, 4, 5, and 6. Through Pitot pressure measurements and flow visualization, the study reveals that the sonic air tabs effectively reduce the core length of the Mach 2.1 jet across all nozzle pressure ratios. The accelerated mixing of the Mach 2.1 jet with the ambient fluid, facilitated by the air tabs, results in shorter core lengths. Importantly, the mixing enhancement by air tabs intensifies with increasing injection pressure ratio for all nozzle pressure ratios, with the maximum reduction in core length consistently occurring at an injection pressure ratio of 6. The observed maximum reductions in core length for nozzle pressure ratios 3, 4, 5, and 6 at an injection pressure ratio of 6 are 41.3%, 60.8%, 43.7%, and 43.5%, respectively. Visualization results confirm the air tabs’ effectiveness in attenuating waves within the jet core, with the weakening of waves increasing with higher injection pressure ratios. These findings contribute valuable insights into optimizing supersonic jet performance through fluidic control techniques.