Citizen Science activities were performed in the framework of the project “Marine Litter Citizen Science Approach (ML-CSA)” carried out by CNR-ISMAR in collaboration with CNR-IFC and INGV during 2022. The students of 7 classes in a High School of La Spezia (Italy) were guided how to construct low-cost smart-drifters equipped with a GSM tracking system in order to track marine litter coming out of Arno’s river mouth. The students studied the distribution of the plastic litter through the implementation of real “dispersion experiments”.