Background <p>Problematic social media use (PSMU) has become a critical public health concern. However, little is known about how the associations between PSMU, mental health, and substance use differ depending on participation in distinct types of extracurricular activities.</p> Objective <p>The objective of this study is to examine how the associations between PSMU, mental health, and substance use vary across network models that include different types of extracurricular activities.</p> Methodology <p>A representative sample of 14,588 Czech adolescents (50.69% boys, mean age 13.6 ± 1.7 years) was used from the 2022 Health Behaviour in School-aged Children study. A network analysis based on undirected mixed graphical models was used to assess the associations. Separate networks for each extracurricular activity type were estimated and compared.</p> Results <p>When individual sports were included in the network, the association between alcohol use and PSMU was no longer observed. In both the community-based activities and individual sports networks, the previously observed positive association between irritability and PSMU-related family conflicts (w = 0.05) was absent, and the association between irritability and social media escapism was weaker (w = 0.08 → 0.03). Only sports-related activity types were negatively associated with losing interest in extracurricular activities due to PSMU, particularly individual sports (w = − 0.10). Conversely, community-based activities were positively associated with PSMU-related deception and family conflicts (w = 0.05). However, no notable differences in the network structure were observed for artistic activities or team sports.</p> Conclusion <p>The study underscores the contrastive nature of extracurricular activities and highlights the need for more nuanced approaches when examining their role in PSMU.</p>