In this study, the group sand play technique (GSPT) was applied to athletes who struggle with teamwork due to low mutual understanding and poor inter-teammate reliance. The process of team improvement was examined through group sand play. Subjects included 14 female athletes who were regulars on their team. A total of 14 sessions were held during the intervention periods, and were divided into two parts; the first took approximately one month and the second approximately a week. On average, each player attended 4.0 sessions of group sand play (range; 3–5 sessions).

Developmental changes brought about by the intervention were examined in four ways: (1) psychological scales, including the scale of dialogical athletic experience, the collective efficacy scale and the diagnostic inventory of competitive ability for athletes, (2) reflection on team performance and dynamics, (3) interviews of athletes and reflection of the facilitator after each GSPT session and (4) coach’s observations of performance improvement.

Improvement in team dynamics was realized in the following four ways: (1) GSPT helps teammates come to an understanding of problems in team dynamics, (2) mutual understanding at the image level is gained through GSTP, (3) GSTP becomes a catalyst for the team learning to cope with team problems and (4) GSPT experiences and training activities run parallel to each other and interact on the athletic field.