This dataset contains CTD (conductivity, temperature, depth probe) data and additional parameters for stations conducted during the cruise SO301. Additionally it contains corresponding navigational data from the ships positioning system. The stations were executed in December 2023 to detect possible hydrothermal plumes at the Kairei Vent Site at approximately -25° latitude and 69° longitude. The data was measured with a CTD rosette system and processed to correct sensor uncertainties and remove outliers. The original sample frequency of 24 Hz was averaged to 1 Hz. Some thermodynamic properties were not processed with the standard SeaBird software but according to the TEOS10 standard.