Participation in physical activity may influence health outcomes, so its quantification is important. There is little data on adolescent physical activities. Recall of physical activity in the preceding year was obtained from a birth cohort of 799 fifteen-year-old adolescents in New Zealand using a modified version of the Minnesota Leisure Time Activities Questionnaire. Mean total participation times were relatively high, with 612 hrs/year (1.68 hrs/day) for males and 401 hrs/year (1.1 hrs/day) for females. Individual total participation ranged from less than a minute to 6.5 hrs/day. Over 10% more females than males reported netball, equestrian activities, and dancing, and at least 10% more males reported cricket, rugby, fishing, soccer, squash, golf, and surfing. Ranked by mean participation time, equestrian activity was highest for females and walking was highest for males. Cycling and swimming represented the largest proportion of total group participation time. The sample will be followed up at age 18 years.