This chapter shares insights into the development and use of Fundisana Online, an ESD e-learning teacher education programme, in teacher professional development for mainstreaming education for sustainable development. We describe how SADC REEP and SWEDESD are working in partnership with teacher education institutions across the SADC region to develop the regional ESD course, Fundisana Online. We describe the collaborative process in building the Fundisana course elements. These elements include key competences for sustainable development, relevant content within and beyond subject borders, effective pedagogic methods to support the learning process and the use of a blended learning approach to integrate pedagogy and technology.