The present study aimed to clarify psychological and behavioral changes in children engaged in long-term yacht activities. For study 1, we interviewed 5 expert junior sailing coaches to clarify the contents of experiences and the psychological and behavioral changes the children experienced as a result of long-term yacht activities from the perspective of the coaches. The results indicated that the "sailing experience" and "experience associated with sailing" components of long-term yacht activities influenced psychological and behavioral changes in children. Moreover, the possibility of improved metacognition as a characteristic of long-term activities was suggested. For study 2, we conducted a questionnaire on 133 junior yacht club members to confirm the validity of a hypothetical model developed based on the results of the interviews with expert junior sailing coaches. As a result of path analysis, in terms of psychological changes in children influenced by the content of long-term yacht activities, positive influences were found for "experience in environmental stimulation", "recreation experience", and "relationship experience with other people" in "metacognition". Regarding the influence on behavioral changes in children resulting from psychological changes, positive influences were found for "metacognition" on "self-action" and "cooperative action", and also for "empathy" on "self-action".

These results suggest that: a) psychological effects differed with the contents of activities; b) metacognition increased as a peculiar effect of long-term activities; and c) psychological changes in outdoor activities led to behavioral changes.