The file contains data from the autonomous surface vehicle HALOBATES. It gathered Essential Climate Variables (ECVs) like sea surface temperature (SST) and salinity (SSS). Data were collected during RV Heincke cruise HE644 from 10 to 31 July 2024 in the German Bight, North Sea. HALOBATES measured conductivity, temperature and pH at seven depths. Vertical resolution was ~10 centimetres. Depths spanned the near-surface layer (NSL, at 30, 40, 50, 60, 85, and 100 cm) to the sea-surface microlayer (SML, ~ 80 µm). NSL water was collected with tubes on a bow-mounted ladder. SML water was collected using six partially submerged glass disks. Water from all sampled depths, including the SML, reached the CTD sensors via a pumped flow-through system. Additional temperature sensors were mounted beneath the catamaran corresponding to depths of the flow-through system inlets. Salinity was corrected with discrete water samples. Additionally, offsets between the CTDs were corrected. Two data loggers with meteorological stations recorded wind speed, air temperature, relative humidity, solar radiation, GPS positions, and others. Upward and downward facing pyranometers and pyrgeometers mounted on the research vessel measured net radiative fluxes for short- and longwave radiation. A disdrometer also mounted on the vessel measured precipitation. The research vessel kept an average distance of 500 metres from HALOBATES which was operated manually or via autopilot. Autopilot involved pre-defined waypoints whilst manual involved steering HALOBATES with a remote control or drifting with surface currents during station work. The dataset includes quality flags 0-4 with flags 1 and 2 are ready for use. See metadata for more information.