Assessing psychological indicators such as positive behavioral skills in the context of adolescent personality development during the pandemic era is highly relevant: the growing problem of peer disrespect among adolescents who participate in sports has recently become an undeniable scientific issue. This study aimed to analyze positive behavioral skills in the cadet (U16) and junior (U18) age groups of young basketball players during the COVID-19 pandemic. The participants were 378 male athletes (age 16.36 ± 1.15 years). Results revealed that U18 athletes are more capable of taking responsibility, positively evaluating themselves, behaving pro-socially with teammates, cooperating, demonstrating assertiveness, demonstrating self-control, and managing emotions than U16 adolescent athletes. When comparing the effect sizes in the current study during the pandemic with similar studies by other authors, the pandemic may have had a larger negative effect on some positive behavioral skills (ability to control emotions, social responsibility skills, cooperation skills) in U16 athletes than in U18 athletes, as the effect sizes were small before the pandemic and moderate during the pandemic in the current study. This study’s results may be useful for developing and implementing a young athletes’ education program based on a comprehensive model of positive behavioral skills that include the indicators analyzed.