In this paper, we explore how a Norwegian teacher education institution promotes education for sustainable development (ESD) through a residential field course. The residential field course was located in a mountain area and data were collected through participant observation. The data included--together with instructional artefacts--evaluation schemes and assignments written by the student teachers, and the analysis was based on categories for science ESD. Through exemplary teaching experiences in an outdoor environment and pupil-active teaching methods, such as inquiry learning and phenomenon-based teaching, the student teachers gained experience in outdoor education and of stepping into the unknown in a safe learning environment. This was further connected to ESD pedagogy.