This study´s aim is to produce knowledge about the process of implementing a service user driven organized social activity initiative at the Health Center for Undocumented Migrants, and to generate insight into its potential for enhancing psychosocial wellbeing. Irregular migrants living in Norway often experience challenging lives, including everyday vulnerability and exclusion. This, combined with the traumas that many have experienced prior to seeking asylum, results in a potentially high risk of mental health problems and distress. Experiences from a mental health project (2011-2014) at the Health Center for Undocumented Migrants in Oslo indicated that service-users might benefit from organized social activities that facilitate fellowship, belonging and social interaction. The Health Center therefore, in conjunction with this study, organized and implemented a social activity initiative. The activities were mostly organized and implemented by service-using participants. All the service users at the Health Center who showed an interest, regardless of gender or background, were welcome to participate in the activities. The data collection period corresponded to the activity initiative period and spanned from May 2018 to December 2018. Data collection included observations and ongoing conversations conducted at the planning meetings and during the activities, as well as six in-depth, semi-structured interviews with both service using and non-servicing using participants. Approximately 34 participants were included. Findings indicate that the initiative entailed sources of both potential benefit and harm for the participants. It became a challenge to maintain the sustainability of the planning group, as service-using participant attendance was presumably dependent on both identifying with the initiative and having material needs covered. There was also a seeming tension between the Health Center and the service users, as there seemed to be differences in covert notions of deservingness and who the ideal activity participants were. The activity initiative included several “silent participants” who were potentially exposed to harm in terms of exclusion, rejection, obligation, disappointment and frustration. On the other hand, among a group of participants with the same ethnic background who frequently attended, these activities were identified as potentially contributing to well-being, fellowship, and positive psychosocial moments. There is a growing emphasis on user involvement in the service provision context and an increased focus on psychosocial initiatives within the humanitarian field. This study can therefore be of potential contribution to a service concept and field of practice that are growing in relevance.