According to the curricula in various countries, teachers in the subject areas of science, social science and language are often expected to collaborate on cross-curricular issues such as sustainable development (SD) in the 9-year compulsory school. This study is based in Sweden and investigates teachers' teaching traditions. The overall aim of this study is to understand what educational content teacher teams can offer students through cross-curricular collaborations. The specific aim in Part 1 of this article is to discern the distribution of teachers' teaching traditions from different subject areas. Part 2 offers a reflection tool for teachers and teacher teams to discern teaching traditions. The results show that teachers from different subject areas stress different yet complimentary aspects of environmental and sustainability (ESE) teaching. A fair distribution of teaching traditions in a teacher team will offer students better learning opportunities to develop and enhance their action competence for sustainable development.