An updated procedure for a CTD-oxygen calibration along with new data processing was applied to recent hydrographic cruise data in the Coral Sea during the Cruise “BIFURCATION” in September 2012. After a brief introduction with the scientific context (section 1), we describe the contents and acquisition models of hydrological and chemical data that are used for the calibration (section 2), the post-cruise calibration method (section 3) and the calibration results (section 4).