This study explores the role of specific sustainability education pedagogies in developing preservice teachers' sustainability consciousness (SC). The participants were 77 Greek preservice teachers from a Department of Primary Education, organized into two cohorts (N[subscript 1]=30, N[subscript 2]=47), from two consecutive semesters. Data were collected through (a) the use of the SC scale, administered before and about two weeks after the end of project and (b) reflective discussions, in the form of interviews, with the groups of preservice teachers at the end of the project. Questionnaire data were analysed using significance testing, 95% confidence intervals, and effect sizes, while from interview data bottom-up categories were developed. Analysis revealed a significant increase in the Total SC scores and in the Knowledge and Social Aspects scores in both cohorts, while Environmental scores were significantly increased only in cohort 1. Moreover, from the interviews it was concluded that the Education for Sustainable Development (ESD) pedagogies of site visits and the associated worksheets and activities, along with concept maps were by far the most influential factors affecting preservice teachers' learning, while general principles of teaching (e.g. students' engagement during teaching, the practicing of theoretical concepts) were also identified.