Lifestyle sport activities (e.g. parkour or skateboarding) are considered attractive and beneficial for a long-term commitment to physical activity (PA) and might be a great opportunity for adolescents who do not feel comfortable in an organized or competitive atmosphere. The purpose of the study was to assess whether participation in lifestyle activities is associated with moderate-to-vigorous physical activity (MVPA), out-of-school vigorous physical activity (VPA), and sedentary behaviour in adolescents aged 10–15 years, with major demographic variables (sex, age, socioeconomic status) being taken into account.