The ruck area is responsible for the second-highest number of rugby union injuries, therefore it is necessary to investigate and understand the ruck better for improved player safety. The study aimed to investigate and compare incidents of legal and illegal ruck cleanouts in non-professional youth rugby. Using Nacpsort Scout Plus software, 118 South African Rugby Union under 18 Youth Week tournament matches were coded between 2015 and 2019. In total, 35,545 ruck cleanouts were coded, of which 32,641 (91.8%) were legal and 2904 (8.2%) were illegal. Of the 2904 illegal cleanouts, 2676 (92.2%) were deemed ‘not dangerous’ and 228 (7.8%) were considered ‘dangerous’. The ‘dangerous’ ruck cleanouts represented 0.6% of the total ruck cleanouts. Of the most common illegal ruck cleanouts, ‘not supporting own body weight’ were mostly ‘not dangerous’ (2498; 99.4%, p = 0.01); and all ‘neck rolls’ were considered ‘dangerous’ (147; 100.0%, p = 0.02). The findings of the study suggest player behaviour can still be improved, with regular participation in regular safe and effective technique training drills. The risk of injury during the ruck can further be influenced positively by coaches, through regular coaching and training on safe and effective ruck techniques.