Aerosol measurements collected during six oceanographic campaigns carried out in 2021 and 2023 in the southwestern Indian Ocean are presented and analyzed in this paper. The results highlight large variability in the aerosol concentration, size, and water vapor affinity depending on in situ conditions and air mass transport over the ocean. Marine aerosol chemical composition is highly variable over this region and should be considered to better study the impacts of aerosols on regional weather and climate.