This data was collected during the ATL2MED demonstration experiment, which took place between October 2019 and July 2020, when two Salidrone vessels equipped with scientific instruments sailed from the North-East Atlantic Ocean to the Gulf of Trieste in the Mediterranean Sea. Fixed stations MIRAMARE, DYFAMED, W1M3A, E2M3A and PALOMA, the R/V Meteor, and two gliders also took part in the experiment. Involved institutions/projects/company were: GEOMAR, CNRS, LOV, PLOCAN, OSCM, IH, SOCIB, OGS, HZG, CSM, CNR-ISMAR, CNR-IAS, ICOS-OTC, and Saildrone Inc.