Summary: The final project proposed was carried out during the academic year 2013-14 and is part of the Master's Degree final project, which aims to implement the knowledge acquired in the subjects that make up the professional track. In particular, the Service Learning experience presented here developed a unit for teaching Spanish as a foreign language to the Catalan prison population. In order to adjust the teaching materials to the reality of the classroom and meet the needs of potential users, the student seeks to knowacquired firsthand knowledge of the real context of teaching and learning by holding interviews with the head of training of the Tarragona prison and the staff that usually taught Spanish classes in the prison. Class observation was also used as a tool to better meet the requirements of regular users and classes. The ultimate goal was for the teaching materials to remain available to teachers in charge of Spanish classes in Catalan prisons so that they can be used in the classroom.