Environmental education researchers argue that pre-service teachers have a limited understanding of education for sustainability. The research described in this article applies a phenomenographic approach to investigating variations in how a representative cohort of 30 pre-service teachers, at various stages of completing an education degree at a small regional Australian university, understands the concept of education for sustainability. The results distinguish four related but distinctive categories of descriptions: (1) education that is continuous; (2) education about ecological systems and environmental systems; (3) education that is active, hands-on, local and relevant; and (4) education for the future. This paper discusses the four categories of descriptions and their implications. Outcomes of the research were used to inform course content, structure and pedagogies with the intention of more adequately preparing pre-service teachers to implement education for sustainability. (Contains 1 table.)