This dataset includes infrasound array waveforms recorded during eruptive activity at Mt. Etna, Italy, on June 20-21, 2021. During volcanic eruptions, the injection of volcanic ash into the atmosphere poses a well-known danger to aviation. To predict the dispersal of airborne ash and identify high-risk areas, scientists rely on observations from volcanology, as well as empirical and numerical models. These models heavily depend on what are known as eruption source parameters, which include the rate of pyroclastic material ejected from volcanic vents and the maximum altitude achieved by eruption plumes. In recent times, infrasound has gained popularity as a valuable tool for monitoring volcanoes, and researchers are continuously exploring its potential for real-time assessment of eruption source parameters. The dataset provided here was used to showcase the potential of infrasound data for near-real-time evaluation of eruption rates. Our analysis of the infrasound array data allowed us to identify coherent arrivals during the eruptive activity. By integrating these signals, we estimated the volume flow rate and flow velocity at the vent. The flow velocity values we obtained at the vent during peak paroxysmal activity were found to be between 50 and 125 meters per second, which aligned with independent estimates derived from other ground-based remote sensing data. Finally, using the flow velocities derived from infrasound we performed numerical modelling of ash plume rise to estimate the maximum height achieved by the eruption column.