Early adolescence is a critical developmental period marked by emotional, behavioral, and biological changes. The COVID-19 pandemic disrupted adolescents’ daily routines, potentially producing lasting effects on mental and physical health. This study investigated anxiety and depressive symptoms, risk of extreme social withdrawal, use of technological devices, physical activity, and sleep–wake functioning in 276 early adolescents (54% females; Mage = 12.28, SD = 0.81) living in a forested and geographically isolated area of Emilia-Romagna in Italy. Participants completed validated self-report questionnaires assessing internalizing symptoms, use of technological devices (including problematic online gaming and smartphone use), gaming motivations, physical activity, chronotype, sleep disturbances, and daytime sleepiness. Scores on the anxiety and depressive symptom scales were within the normative range, except for scores on certain scales suggesting a moderate degree of severity that was not clinically significant. Females reported higher levels of anxiety, depressive symptoms, and problematic smartphone use, whereas males showed greater involvement in problematic online gaming and stronger achievement-, social-, and immersion-related motives. A substantial proportion of participants reported excessive daytime sleepiness (42.4% of females; 26.1% of males). Significant patterns of association were found among internalizing symptoms, domains of sleep–wake functioning, use of technological devices, and risk of extreme social withdrawal. Overall, these findings support the relevance of predisposing preventive strategies aimed at improving different domains of physical and mental health among youth in underserved or geographically isolated communities.