Despite growing evidence for a relation between individuals’ time use practices, their wellbeing, and potential negative outcomes regarding the vision of a sustainable future, knowledge on time-related learning outcomes and how to foster them remains scarce in Environmental and Sustainability Education scholarship and practice. In this explorative study, we aimed to find out how time use competence can be fostered within the framework of a school intervention based on the pedagogy of self-inquiry-based learning. We delivered the intervention to 156 students aged between 14 and 21. Applying Action Research, we inquired into students’ subjectively experienced, time-related learning experiences resulting from participating in the intervention. We collected a series of qualitative data (e.g. reflexive journals, time use documentations, or semistructured interviews), which we analyzed using template analysis. The overall contribution of our study is twofold: First, we provide a novel pedagogical approach allowing learners to experientially access the complex and fluid topic of time within Environmental and Sustainability Education. Second, we show that this approach can enable students to organize their time in a more self-determined and needs-oriented manner. Most students experienced the intervention as positive and acquired abilities helping them to address daily struggles with their time use, often resulting in less resource-intensive time use. However, the experiential format of the intervention also posed challenges to some students. Finally, we identified broader limitations of intending to foster time use competence through isolated learning activities. We discuss our results regarding the broader potential of educational interventions to contribute to the vision of sustainability through time-related learning. We emphasize that a whole-school approach might be particularly promising to foster time-related learning outcomes while also transforming the prevalent time-related structures of schooling. However, schools’ systemic embeddedness and subordination to political educational authorities also make such an approach challenging.