Introduction: Attempts to embed social prescribing into practice are often limited by fragmented systems, medicalised pathways, and narrow implementation models. This research introduces a service ecosystem perspective to better understand these systemic barriers. A service ecosystem is a dynamic, multi-actor system in which value is co-created through shared institutions, resource integration, and relational interactions. This approach foregrounds the often-overlooked dynamics that shape how social prescribing is funded, commissioned, and experienced, highlighting the importance of institutional alignment, local assets, and lived expertise. This research explored how a service ecosystem lens can inform the development of a more sustainable, locally responsive model of social prescribing, and addressed the following research questions: (1) what are the characteristics of the current social prescribing ecosystem in a regional Australian context?; (2) what service ecosystem transformations are needed to enable system-wide implementation? Method: Four co-design workshops were conducted in a regional South Australian community (n = 72) involving health, social, community service professionals and community members. Facilitated by a multi-stakeholder steering group, workshops followed a structured co-design process. Data from discussions, artefacts, and fieldnotes were descriptively analysed using a theory-informed approach. Results: The current service ecosystem was highly medicalised, GP-dependent, and lacked visibility and legitimacy for non-clinical actors. The co-designed model proposed: (1) decentralised entry pathways; (2) new link worker roles including community-based navigators; (3) shared digital infrastructure; (4) feedback loops for accountability; and (5) public engagement to shift perceptions and build legitimacy. Discussion: Viewing social prescribing as a service ecosystem, rather than a singular intervention, reveals critical leverage points for change. This research also highlights how embedding lived expertise and local knowledge through co-design enables more responsive, place-based solutions. The findings offer practical guidance for funders, commissioners, and policymakers to reconfigure institutional arrangements, unlock community capacity, and build sustainable cross-sector infrastructure for health and wellbeing.