PurposeThis paper examines the professional capital related to climate change education, as reported by Chilean teachers, in their efforts to address climate change in schools.Design/methodology/approachThis paper employs a sequential mixed-methods approach, utilising data from a national survey of teachers in Chile. We conducted a cluster analysis on responses to a set of items related to climate change education practices, using statistical methods to compare and characterise the resulting clusters. Additionally, we explored two case studies through a thematic analysis of interviews to gain insights into teachers' specific climate change education practices and their reflections on these. Finally, based on the results, we reflect on teachers' professional capital for climate change education and discuss the implications.FindingsTeachers report engaging in climate change education practices such as integrating climate change topics into the curriculum, incorporating it into lesson planning, utilising students' experiences in teaching and focusing on developing students' organisational, communication and representation skills in the context of climate change. They also facilitate classroom discussions on climate change and environmental issues through current events. Teachers in this group identify as activists and science educators, describing themselves as informed about climate change while feeling both optimistic and concerned about its impact. The teachers interviewed for the case study demonstrate a developing professional capital for climate change education, a strong commitment to environmental issues and nuanced understandings of activism and climate action.Research limitations/implicationsFuture research can explore perceptions of activism and climate action in relation to classroom practice. Also, research can explore if having a national curriculum in Chile impacts teachers' professional capital for climate change education development. In curriculum policy, this study points to constructing decision options regarding approaches for climate change education professional capital development, which can also be part of research endeavours.Practical implicationsThe study points to favouring differentiated professional development opportunities for fostering climate change education professional capital. Survey results and case studies show the need for acknowledging developing practices and tailoring professional development experiences. In curriculum policy, this study points to constructing decision options regarding approaches for climate change education professional capital development.Originality/valueOur analysis operates at the conceptual intersection of teachers' professional capital and climate change education. We explore forms of professional capital that challenge traditional notions of activism in teaching, particularly in relation to climate change. Additionally, this work contributes to the existing body of knowledge on climate change education in Chile and offers implications for research, practice and policy.