This dataset contains Conductivity–Temperature–Depth (CTD) measurements collected in fjords of South Georgia during the SRV Saoirse expedition in November–December 2019. The dataset includes vertical profiles of seawater salinity, temperature and density obtained with a CTD48M memory probe (Sea & Sun Technology GmbH) at stations distributed across glacier-influenced fjord systems, including Cumberland Bay and adjacent coastal settings. The measurements document the hydrographic structure of sub-Antarctic fjords during the austral spring–summer transition, characterized by strong near-surface stratification driven by glacier meltwater input and by the interaction between locally modified fjord waters and Southern Ocean water masses. At each station, CTD casts provided measurements of water-column properties from the surface to near-bottom depth. The dataset includes sampling date, station coordinates, and vertical profiles of salinity, water temperature, and seawater density. The dataset has been used in studies addressing fjord hydrography, glacier retreat dynamics, sedimentary processes, and benthic protistan ecology. Parts of the dataset were presented and interpreted in Majewski et al. (2023) and subsequent related studies.