This paper promotes the value of including many stakeholders in service development. The experience of co-creative service development is examined through the lens of action research. Engaging multiple stakeholders in face-to-face, in simultaneous joint activities, from various organisations, with different levels of hierarchy, and dissimilar positions, may increase the diversification through the broadness of the information, knowledge, and experiences, and increase the amount, and quality of the development suggestions. This paper is an attempt to tell the story of action research, and how it was applied to increase the understanding of the usefulness of multiple stakeholders in service development. Outcomes of a research project are presented. The paper ends with discussion of the theoretical and practical implications of the conducted research.