Insight into the unique benefits of sport participation above and beyond those associated with participation in other physical activities among adolescents is limited in Aotearoa New Zealand (NZ). The purpose of this study was to examine the association between wellbeing and organised sport participation among adolescents whilst accounting for demographic characteristics and other recreational physical activity. Demographic characteristics (age, gender, ethnicity, deprivation, (dis)ability status), organized sport, recreational physical activity, and wellbeing were assessed in cohorts of NZ adolescents (11–17 years) between 2017 and 2019. After adjusting for demographics, better wellbeing was associated with participation in any recreational physical activity (OR = 2.49, 95%CI = 1.97–3.13), meeting physical activity recommendations (OR = 1.63, 95%CI = 1.47–1.81), and each additional hour of recreational physical activity (OR = 1.03, 95%CI = 1.02–1.04). After adjusting for demographics and overall recreational physical activity participation, better wellbeing was also associated with participation in any organized sport (OR = 1.66, 95%CI = 1.49–1.86), and each additional hour of organized sport (OR = 1.09, 95%CI = 1.07–1.11). Although participation in recreational physical activity appears to be beneficial for wellbeing, organized sport appears to offer unique additional wellbeing benefits. Positive experiences of organized sport participation may offer additional wellbeing value above and beyond other recreational physical activity types in young people who are active.