Municipalities face increasing pressure to deliver efficient and secure digital solutions. While this challenges all municipalities to engage in digital transformation (DT), resource disparities contribute to digital inequality as smaller actors struggle to allocate financial means and secure competency. Inter-municipal collaboration is crucial for addressing these challenges, yet research on its role in DT remains limited. This paper examines how DT unfolds in inter-municipal collaboration through a case study of two Swedish municipalities striving for equal welfare as a human right. Using longitudinal data and a collective social action perspective, we identify the trajectories of different types of DT, enabling mechanisms and sub-mechanisms that facilitate progress, and their role at various stages of collaboration. By extending existing frameworks, this research deepens the understanding of inter-municipal DT and provides valuable insights for practitioners working to enhance digital public services through collaboration.