Raw data acquired by a thermosalinograph (SBE21, Sea-Bird GmbH) in combination with an external temperature sensor (SBE38, Sea-Bird GmbH) aboard RV Heincke were processed to generate a calibrated, quality-controlled dataset of seawater temperature and salinity. The raw sensor data were initially retrieved from the DSHIP database (https://dship.awi.de) at a temporal resolution of 1 second and converted into temperature and conductivity using the pre-deployment calibration coefficients. The thermosalinograph system aboard RV Heincke is typically replaced after each expedition season, with a recalibration conducted at the manufacturer's facilities after each exchange. After post-cruise recalibration of the instruments, additional correction factors were calculated and applied to account for sensor drift. Salinity was calculated from internally measured temperatures and conductivities following the Practical Salinity Scale (PSS-78). The processed dataset is provided as 1-minute averages of salinity and seawater external temperature, synchronized with the positional data from the expedition's master track. Quality flags were assigned in accordance with the SeaDataNet Data Quality Control Procedures (May 2010).