Abstract This study explores the impact of two Service-Learning (SL) projects on student teachers’ preparation and perceptions in relation to literacy teaching in English as a foreign language within CLIL programmes. The projects offered hands-on training in preparing and delivering lessons applying Rose and Martin’s (2012) Reading to Learn (R2L) approach to support children at two Madrid primary schools implementing CLIL with high proportions of at-risk pupils and socioculturally diverse student bodies. One hundred and thirteen undergraduate student teachers specialising in English as a Foreign Language at the Complutense University School of Education participated in the SL projects. The projects’ goals included developing the students’ civic engagement and disposition to gain understanding of the potential of a systematic, evidence-based approach to literacy pedagogy for guiding all pupils to acquire the reading and writing abilities needed for educational success. Data from questionnaires, focus group interviews, and reflective journals were collected and analysed. Student teachers faced the challenges of apprehending and effectively applying the R2L strategies in classrooms characterised by pupils’ widely ranging levels of preparation for reading and writing in English. Their reflections show evolution towards readiness and awareness of the possibilities of adopting proactive measures, such as systematic literacy instruction, in order to ensure the progress of pupils as they face the challenges of CLIL in the context of socioeconomic and educational inequity within classrooms and across schools.