Abstract Southern Hemisphere westerly winds are important drivers of Antarctic and sub‐Antarctic environmental change. Short observational wind records prevent us from fully understanding the scope of their variability. Proxy records provide valuable tools to extend environmental records. Here we present a novel wind study based on the use of windblown diatoms preserved in layers from the first firn core drilled in the sub‐Antarctic Bouvet Island. The firn core diatom record is comprised of high‐concentrations of pristine and locally sourced Southern Ocean marine taxa. This record is the first to characterize the diatom diversity and abundance actively entrained by winds in the sub‐Antarctic region. Correlation analyses reveal interannual diatom abundance variability is primarily driven by wind strength changes in the core of the westerly wind belt. These results validate using the Bouvet Island diatom record as a proxy for reconstructing past atmospheric circulation variability over the Atlantic sector of the westerly wind belt.