To investigate the cross-slope freshwater exchange in the Australian-Antarctic Basin between 80 and 150°E, the stable oxygen isotopic ratio (δ18O) was evaluated based on top-to-bottom hydrographic sections by R/V Kaiyo-Maru in 2018/2019 summer. The southern flank of the Antarctic Circumpolar Current (ACC) flows eastward in the north and the Antarctic Slope Current (ASC) flows westward along the continental slope in the south of the analysis domain. We obtained the spatial δ18O structure characteristics of water masses that were transformed by freshwater input from the highest Circumpolar Deep-Water value. δ18O-salinity relationship in the near-surface layer revealed a regional difference between the upper and lower continental slopes. The fractions of sea ice melt and meteoric water were estimated using mass-balance calculations assuming constant endmembers with no spatial and temporal variabilities. The fraction of sea ice meltwater was usually highest at the surface and rapidly decreased to the temperature minimum layer, while the meteoric water fraction was also highest at the surface, gradually decreasing to the temperature maximum layer. The area-average of sea ice meltwater integrated above the temperature minimum is about 0.7 m water-equivalent, with large accumulation off and downstream of the coastal polynyas.