Even though the urge to transform educational practices towards sustainability has been widely recognized, teachers struggle with implementing socioscientific issues (SSI) such as climate change and loss of biodiversity into their lessons. While the research on SSI grows, the literature remains limited in terms of (i) the use of SSI in facilitating education for sustainable development (ESD), and (ii) teachers’ professional learning of SSI-based instruction as a means towards ESD. In this empirical study, we aimed at characterizing five STEM pre-service teachers’ pedagogical design capacity (PDC) by focusing on what resources they use and how they interact with these resources to design SSI-based instruction to teach about the sustainable development goals (SDGs). For this qualitative study, the data were collected through field notes, reflection reports, and semi-structured interviews. Our results reveal that pre-service teachers referred to teacher resources the most, followed by collaborative resources, and instructional resources during their design. Even though their use of resources shows strong connections between SSI and their pedagogical content knowledge, preservice teachers’ consideration regarding assessment remains inadequate. Furthermore, our study shows that professional development sessions have the potential to foster pre-service teachers’ use of PDC resources to address ESD.