A high sense of belonging to the community and physical activity are associated with improved mental health in older people. The present study tested a model incorporating physical activities performed alone and with others as predictors of sense of belonging, depression and suicide ideation. One hundred and ninety four retired adults (87 males, 107 females, mean age 68 years) completed the Yale Physical Activity Survey, the Sense of Belonging Instrument, the Suicide Subscale of the General Health Questionnaire and the Zung Depression Inventory. Within the context of the model, neither participating in physical activities alone, nor with at least one other person, predicted sense of belonging, depression or suicide ideation. Having the abilities and motivation to belong was a predictor of participating in physical activities with others and actual feelings of belonging and contributed to predicting mental health in retirees. It was concluded that simply performing activities with others was not associated with a sense of belonging or mental health. Rather, sense of belonging may need to be facilitated in order for mental health to be enhanced.