On oyster table in the Thau lagoon (WGS84 Lat. 43.379°N Long. 3.5715°E), Ifremer measures hydrological parameters (temperature, salinity) at high-frequency (depth 1 to 2m). Data loggers (NKE: SMATCH and STPS) measure every 15 minutes. To limit biofouling, there is a localized chlorination at the sensor (SMATCH) and a regular rotation of data loggers (STPS). The brand of sensors is WTW. These devices are calibrated regularly with a connection to ITS90 for temperature and IAPSO standards for salinity. The data are qualified by calibrations in the laboratory. For salinity: calibrations in-situ (since 2015), comparisons between sensors and post treatment correction (since 2019) are also conducted. A maximum permissible error (MPE) is calculated with the data, taking into account the measurement bias and the measurement uncertainty (k=2).