Within the MARLISCO EU funded Programme (2012-2015) the educational material “Know Feel Act! To Stop Marine Litter” was prepared to inform, sensitise and enable European teachers and students to take action to tackle the problem of litter in our seas and coasts. The material has been designed to primarily serve youth aged 10-15 yrs, but can be used also by educators outside the formal schooling system. The material contains 17 activities, each combining a learning activity part (4 pages) and a worksheet for students (1 page). The activities are self-standing and can be applied separately or combined in clusters, so to meet the needs of the educator.  Originally authored in English in 2014, the material has been adapted and translated in totally 17 languages (European as well as Russian and Arabic!) available at http://www.marlisco.eu/education.en.html while the Greek one can be downloaded from our site.