Background: The number of adolescents that drop out of soccer has increased the last decades. As soccer participation may represent a substantial part of adolescents’ physical activity, efforts to reduce drop-out are important. To develop effective prevention programs, knowledge about why adolescents drop out is needed.

Purpose of the study: Using a prospective design, over three consecutive seasons, we investigate differences in motivation and coach autonomy support between adolescents that stay in soccer and adolescents that drop out.

Methods: Participants were 738 adolescents (462 males and 275 females), 11-17 years old (M = 13.72, SD = 1.77) from soccer clubs in Sweden. Data about demographics, motivational regulations and coach autonomy support was collected in 2019, drop-out data at the end of seasons in 2019-2021. We used Mann-Whitney u-test to analyse potential differences between the two groups. A p-value <.05 was considered a statistically significant result. Cohen’s d effect size was calculated for each comparison.

Findings: Of the participants, 256 (34,7%) dropped out until the end of the 2021 season. Dropouts experienced lower intrinsic motivation (U=55263, N1=479, N2=253, p=.006, d=0,15), more amotivation (U=66358, N1=482, N2=256, p=.042, d=0,13) and less coach autonomy support (U=49566, N1=479, N2=253, p=<.001, d=0,30). Regarding identified motivation (U=57329, N1=482, N2=255, p=.13, d=0,11) and introjected motivation (U=64628, N1=482, N2=256, p=.25, d=0,08) no statistically significant differences were found.

Conclusion: To facilitate motivation and continued soccer participation we propose theoretically informed education programs to help coaches adopt autonomy-supportive coaching strategies.