The dataset includes the continuous water side pCO2/fCO2 measurements made by Finnish Meteorological Institute on BONUS INTEGRAL winter cruise on RV Aranda for monitoring the green-house gases and related parameters 28.02.-11.03.2019. The cruise was one of the two research cruises made within the BONUS INTEGRAL project (2017-2020): https://www.io-warnemuende.de/integral-home.html and https://www.bonusportal.org/projects/blue_baltic_2017-2020/integral. The file includes also the position, speed and heading of the research vessel, as well as air pressure, air temperature, sea surface temperature, sea surface salinity and original pCO2 sensor data used in the calculations.