The data set consists in the ionic composition determined by ion chromatography of the superficial snow sampled in the Antarctic Campaign 2019-20. In the framework of the "East Antarctic International Ice Sheet Traverse" (EAIIST) project, surface snow samples were collected along a traverse from Dome C (75° 06' 01'' S, 123° 20' 48'' E - East Antarctic plateau) toward the geographic South Pole during the 2019-2020 Antarctic campaign. 32 samples were collected using 50 mL tubes by personnel wearing low particulate release clothing, polyethylene gloves to minimize external contamination. The uppermost 6 cm of snow were collected by inserting the tubes into the surface snow of the sampling site upwind and at a sufficient distance from the convoy to reduce the contamination risk. The tubes were kept frozen until the analysis. The cationic (Na⁺, NH₄⁺, K⁺, Mg²⁺, Ca²⁺) and anionic (Cl⁻, NO₃⁻, SO₄²⁻) content was determined by Ion Chromatography. The reproducibility of the measurements is always better than 4% and detection limit are in the range 2-5 ug/l for anions and 0.1-0.6 ug/L for cations. Details on analytical method are reported in the paper Ventisette et al. 2023. The data set is useful to study the spatial distribution of major ions on the inner Antarctic plateau, to understand their deposition and post deposition processes in this area characterized by megadune and wind crust formation (Ventisette et al., 2023). The knowledge and quantification of these processes will allow the interpretation of the ice core stratigraphies in low snow accumulation rate.