The study used an outdoor program for promoting Education for Sustainable Development (ESD) in primary education and investigated the extent to which primary student teachers were prepared to deal with ESD. It also investigated the impact of an outdoor program on primary student teachers' knowledge and attitudes towards sustainable issues, and on their personal responsibility and willingness to be involved in ESD. The present study was part of a larger multifaceted project that attempted to provide an example for training primary student teachers in Education for Sustainable Development (ESD). Fifteen primary student teachers from a university participated in a training program. The program was based on an open-air photo exhibition titled "The earth from above" that focused on issues of sustainable development. Individual interviews were conducted with the participants, at the end of the program, for data collection. Evidence from the interview analysis indicates that student teachers'involvement in the project provided them with specific teaching strategies, and increased their competence and self-efficacy to be involved in ESD. The program also offered them the opportunity to identify the interconnections of environmental issues, and their social, economic and political dimensions. Student teachers realized through their active participation in the planning and teaching process how crucial is their role in cultivating environmentally literate citizens.