We continuously measured aerosol size distributions in the range between 90 nm and 5000 nm in 64 bit resolution with an optical particle sizer (TSI LAS3340). The measurements were conducted at the Air Chemistry Observatory (SPUSO) at Neumayer III Station (Antarctica) between 1 January 2021 and 31 December 2021. The data rely on an original 10-minute temporal resolution and are finally submitted as 60-minute averages. Aerosol size distribution measurements are part of the air chemistry long-term observations at Neumayer III. Details about the instrument can be found under "resources" of the corresponding metadata link: https://hdl.handle.net/10013/sensor.5d9a9253-e118-4744-be3a-05f31551314a