We explore the role of participation in transdisciplinary research in general, and in urban planning research and practice specifically, by scrutinising urban planning pedagogy and the application of spatial methods, and discussing associated challenges and shortcomings. Our literature review highlights, on the one hand, the limited engagement and challenges in integrating participation within transdisciplinary research; on the other hand, the groundedness of spatial methods as well as the increasing attention towards public participation and collaboration within urban planning pedagogy and practice. Against this backdrop, our Cais do Porto case study in Porto Alegre, Brazil, provides an example in which we analyse the dynamics of participation within a transdisciplinary framework, considering specialisation, legal frameworks and upcoming urban development policies. We demonstrate how collaborative interactions between the community and academia produced results that extend beyond official academic records. This chapter exhibits hallmarks of transdisciplinary research as much as it aligns with the goals of SDG 11, characterised by commitment to socially relevant issues, the transcendence and integration of disciplinary boundaries and participatory research. Drawing on our collective urban planning and research experience, this chapter offers valuable insight into spatial methods in transdisciplinary research and practice by emphasising the critical role of participation.