ISMAR-CNR participated in the European Maritime Day event that took place in Brest during 24 – 26th of May 2023 and presented the Citizen Science activities of Nautilos project. During the two days of events in the exhibition area in Brest (Bretagne) there were workshops, plenary sessions, but also theatre performances, interviews and live internet broadcasts. The focus of all activities was our relationship with the ocean, current research, new “blue careers” and the blue challenges we have to face in this ocean decade.