Service-learning is a teaching methodology that promotes students' learning through active participation in experiences of community service. This methodology allows students to engage directly with those to whom it offers a needs- and context-adapted service, very often outside the classroom. While there are numerous projects that follow the service-learning methodology, surveys of experiences carried out at higher education level remain scarce. We performed a survey study with 424 undergraduate students participating in service-learning projects in order to identify the type and level of student participation, the skills and competences acquired; the characteristics of services provided; and the levels of satisfaction of students taking part. We found that the students had a positive perception of the effects of their participation; that the skills and competences developed were primarily teamwork, ethical commitment, adapting to new situations and problem-solving; and that the usefulness of the service was mainly in moral development and commitment.