This paper explores the potentials and limitations of transdisciplinary research on sustainability issues characterized by extensive uncertainty and complexity. Transdisciplinary approaches that support the co-creation of knowledge in collaboration between science and society are advocated in research that aims to explore pathways for societal transformations towards sustainability. However, there is limited research on how co-creation research plays out in practice and what are its implications, in particular with regards to how data collection and analysis can be developed to increase the quality and reliability of the research, and to the roles that researchers themselves play in shaping the research. This paper makes two contributions: First, it offers insight into the design and implementation of co-creation endeavors based on scholarly literature as well as experiences from a research program that seeks to support foresight capacity for sustainable development under geopolitical uncertainties. Second, the paper elaborates methodological support for co-creation research by highlighting the potential of co-dissemination for transdisciplinarity and arguing for a systematic approach to reflection and self-reflexivity. Specifically, the paper reflects on experiences from the ongoing Mistra Geopolitics research program, which explores the intersections between geopolitics and sustainable development, and where co-creation has been at the core since the start of the program. We explore three stages in transdisciplinary research: (i) co-design of the research agenda, (ii) co-production of knowledge, and (iii) co-dissemination. Specifically, we examine the role of non-academic partners, the role of knowledge brokers and facilitation, and the need for flexibility, adaptability and reflexivity throughout the process.