Learning to teach science out-of-field (OOF)--teaching science without the required qualifications or specializations--raises a number of challenges for teachers. This paper uses a spatial-temporal lens to examine teachers' experiences of learning to teaching science subjects OOF over time. The analysis draws on longitudinal interviews with OOF teachers to examine two research questions: (1) How do teachers' allocation to teach science-related subjects OOF change over time?; and (2) What do teachers need to learn when teaching science OOF? Over time, it became clear that there were a number of career trajectories, which were indicative of teachers' future commitment to learn to teach science. Also, various dimensions of the change processes were identified that go beyond simply learning the content and how to teach it. Five categories of learning were identified: content, teaching strategies, students and their learning, the school landscape, and the professional self. The prominence of these categories shifted overtime. Also, teachers articulated which of these learnings arose "because" of having to teach out-of-field, for example, making links between in-field and OOF teaching was important as these links acted like boundary objects. Implications of this study suggest that teaching science OOF should be examined spatially in the context of a teacher's full teaching load at any one time, as well as in the context of temporal career and learning trajectories. Also, research into teachers' experiences of learning to teach OOF should consider the teacher in context, and in relation to teacher learning generally.