Transition is a common characteristic of our lives, particularly in a rapidly changing world. In this context, how careers are enacted has become increasingly varied, requiring new conceptual tools to study the transitions of learners and workers. This paper uses theoretical constructs from the literature on boundaryless career discourse as well as learning and on work transitioning in order to explore the learning pathways of environmental engineers. It thus contributes to empirical work that articulates ongoing transitions (beyond the first job) within ‘occupational and organisational life’, as well as to the understanding of learning pathways as educational and occupational progression. The career stories help us to understand how non-linear transitions emerge, the complexity of these transitions, and the need to attend to broader institutional arrangements within and across education and training, the labour market and the workplace. Through its focus on the environmental engineer, it helps us to understand the processes and outcomes of transitions in an important occupation in contemporary professional work in South Africa. Finally, in a field dominated by research on entry into a first job, the paper also provides much-needed insights into occupational transitions into specialised work.