This article presents the SONAR project ("Subtitulación sOcial para proporcioNar Accesibilidad audiovisual en la univeRsidad" [SOcial subtitliNg to provide Audiovisual accessibility at the univeRsity]). Conducted to assess the validity of the creation of social subtitling networks, its ultimate goal is to better understand the role that social subtitling, as a non-professional translation activity, can play in increasing access to audiovisual materials in academic environments. Following a task-based approach, 55 students from a translation module taught in the third year of the Degree in English Studies at the UNED worked online for two months and subtitled 82 videos. The videos had been selected from the audiovisual repository of the institution. The impact of this practice on the students' general translation and foreign language competences as well as the participants' degree of motivation for future related practices were quantitatively and qualitatively analysed. The results obtained from the experience are an encouraging starting point for the creation of similar collaborative subtitling experiences in higher education environments and confirm the potential impact of such a novel teaching approach.