The provision of mobile technologies in higher education has unquestionably opened possibilities for how we design learning environments. Opportunity arises to explore mobile design features not only for engaging students but also for how we support and develop university teachers. This chapter explores pedagogic principles of designing an online learning environment for the professional development of teachers. Specifically, this chapter looks at programs that enhance teaching and learning skills and capacities for sessional teachers, those on casual, contractual or part-time employment, who play a crucial role at the coalface of student learning. Two cases are presented that demonstrate different, yet complimentary design features of online programs. These cases utilize flexible spaces and enable sustainable opportunities for engagement by promoting greater access and support for sessional teachers’ professional learning.