This article advances Public Service Logic (PSL) by examining how spaces are constructed and navigated within service ecosystems. In this study, ‘space’ is understood as the relational configurations through which actors coordinate, negotiate, and enable action. Based on a study of three citizen-led cross-sector support centres for cancer patients in Sweden, the findings show that the centres address unmet needs, facilitate collaboration, and navigate boundary issues with traditional patient associations. By integrating a spatial perspective into PSL, the study introduces the concept of Public Service Space to explain how cross-sector collaborations sustain service ecosystems through relational arrangements, enabling welfare provision.