The present study was performed to clarify the reasons for the reduction in the amount of time spent by the current generation of elementary school children playing outside or participating in sports, based on opinions from both the children themselves and their guardians and teachers, data that could be used to establish methods of promoting outdoor activities or sports. This survey was conducted using a questionnaire that targeted 3,752 elementary school students in Kanagawa prefecture (broken down into 999 4th grade boys, 891 4th grade girls, 933 6th grade boys and 929 6th grade girls), 5,017 of the guardians of these students (685 males and 4,332 females), and 1,202 education-related personnel (423 males and 779 females). In order to process the results, we categorized the figures into 3 groups of children, adult generation 1 (20 to 30 years of age), and adult generation 2 (40 to 50 years of age), and analyzed them on the basis of Hayashi's quantification theory. In examining the characteristics of play and activities, we found that children played less frequently outside in locations such as open spaces and empty land lots, and that they tended to play alone more often when compared with recollections by adult generations 1 and 2. Furthermore, we found that playing outside or engaging in sports was not passed on to children as types of activity that could be enjoyed in groups. We also observed that the types of play activities children adopted are greatly affected by the media. Regarding the relationship between play activity environments and the variety of outdoor play and sports, we found that regardless of generation classification the experience of playing in natural settings such as mountains, the sea, rivers or similar locations served as a large factor in providing variety for recreational activities, and that participation in sports clubs and the involvement of adults were also major factors in promoting such activities. Based on these findings, we suggest that establishing and maintaining locations where children can play with a sense of freedom, and the involvement of adults in passing on play activities and introducing play-related ideas, are essential for the promotion of outdoor play activities and sports for children.