To date, despite the many recognised benefits of participation in sport, many older people do not participate in it. This study explored the opinions about barriers to participating in sport among non-active older people from the perspective of 463 senior athletes (M = 61.4, SD = 5.5 years) engaged in competitive sports. Participants completed a questionnaire including an incomplete sentence regarding the reason why many older people do not play sports. We analysed their answers using content analysis and performed bivariate analyses to determine possible associations with the sociodemographic and participatory characteristics of the sample. The results highlighted a range of perceived barriers which mostly related to past and present opportunities, and contained significant variations according to age, country of residence, and years participating in sports. These findings contribute to a better understanding of the way in which senior athletes perceive the barriers for the initiation of non-active older people in sports participation which could inform potential measures to promote greater participation in sport as a meaningful leisure activity among this age group.