Complemental to the first FCT workshop, the metrology laboratory of Ifremer Centre de Bretagne carried out a calibration experiment from the 8th to the 12th of October 2012. This experiment was promoted by the Jerico European project (JOINT EUROPEAN RESEARCH INFRASTRUCTURE NETWORK FOR COASTAL OBSERVATORIES), in the framework of a collaborative work proposed by the workpackage 4, “Maintenance and Calibration”, and the “Forum for Coastal Technologies”. The purpose of this experiment was to compare the calibration methods used by different institutes or firms within an inter-laboratory comparison (ILC). In terms of metrology, this comparison will allow the laboratories to assess their performance with respect to the calibration of their sensors. The parameters under investigation were temperature, salinity (conductivity) and dissolved oxygen. To simplify the process and to shorten the time devoted to the comparison, Ifremer proposed to carry out for each participant, a bilateral comparison (Ifremer vs participant) on one or several sensors owned by the participant. All comparisons were simultaneous. The objective (institutes performance) was achieved by comparing the calibration results of the regular calibration of the sensors of the participants with the reference calibrations performed by the coordinating laboratory, the metrology laboratory of Ifremer. The evaluation of the performance was carried out using the reported deviations and/or corrections and corresponding uncertainties of the participants with respect to the measured deviations/corrections and corresponding uncertainties by the reference laboratory