Recently, the carry-over of physical fitness or physical activity from childhood to adulthood has been actively discussed. However, the carry-over effect of participation in organized sports is not well understood, despite the fact that organized sports participation has a number of positive effects on physical, mental, and social aspects. Therefore, the purpose of the present study was to clarify the association of organized sports participation during school age with organized sports participation and sports volunteer participation in adulthood. The data was secondarily obtained from “nationwide questionnaire research for promotion of sports activities according to the life stage” conducted by the National Recreation Association of Japan. This research was conducted with 1,200 Japanese adults (612 males and 588 females) who were 20-39 years old. Path Analysis was conducted with respect to each sex. Regarding association of organized sports participation in school-age with organized sports participation in adulthood, participation in elementary school was related to that of junior high school, participation in junior high school was related to that of high school and adulthood, and participation in high school was related to that of adulthood in males. By contrast, in females, participation in elementary school was related to that of junior high and high school, participation in junior high school was related to that of high school and adulthood, and participation in high school was related to that of adulthood. With respect to association of organized sports participation in school-age with sports volunteer participation in adulthood, only organized sports participation in high school was affected in males, and only organized sports participation in junior high school was affected in females. There is a possibility that participation in organized youth sports has a carry-over effect for adult sports involvement. In order to promote organized sports participation and sports volunteer participation in adulthood, enhancing organized sports participation in school-age would be valuables.