There are currently 43.8 million people living with or after cancer worldwide. Tenovus Cancer Care Sing with Us choirs are a form of activity-based psychosocial intervention for people affected by cancer. Research has found attending these choirs has positive effects; however, the impact of the social aspect has not been sufficiently explored. This study therefore aimed to qualitatively explore the psychosocial impact of attending a Tenovus Cancer Care Sing with Us choir, with attention to the role of social connectedness. A qualitative study was conducted, followed by a routine evaluation of the choirs using quantitative and qualitative methods. Focus groups were conducted with choristers from one choir and evaluation data from all the choirs in Wales was used to compare the qualitative findings from these with survey responses from the larger choir population. Three key themes were identified: individual impact, group experience, and interaction between the individual and the group. This study has offered qualitative support to existing studies which suggest choral singing benefits people affected by cancer. We also explored how being in a choir impacted on members’ social connectedness and subsequent well-being.