In this research, we set out to investigate the phenomenon of ‘co-design’ and explore the applicability of co-design in the complex coastal context. We have turned to investigating design-oriented, collaborative activities aimed at innovative coastal solutions (co-design) and how they strengthen the development of solutions for coastal problems. Co-design provides a means of realising various ends. We observed, for instance, co-design activities with the goal of collaboratively designing engineering solutions to coastal problems. In other situations, the goals of the co-design activities were wider or were aimed at adapting policy. In general, we see that co-design activities aid in identifying (value) dilemmas, clarifying the diversity in actor perspectives, and broadening the potential space for solutions. Co-design activities ideally give different actors the room to work together in a creative and open manner. Local, scientific, practice-based and other forms of knowledge are ideally used in an egalitarian fashion in the search for solutions to coastal management problems. The thesis ‘co-design in the coastal context’ contributes to insights in how to design the co-design activities, reflects upon insights offered by a broad range of literature on co-design in complex systems, and offers usable and practical methods to evaluate such co-design activities.