Purpose: To explore the effects of mobility restriction on the mental health of Ecuadorian young adults. Methods: The current is a cross-sectional study that included 8426 young adults. Socio-demographic and mental health data were collected through an online survey during May and June 2020 in Ecuador. Data on mobility was extracted from Google Mobility Reports. Four aspects of the participants’ mental health were evaluated: eating behavior (emotional eating), depression, sleep quality and sense of coherence using previously validated instruments. Data were analyzed using linear regression using R. Results: Mean age of the participants was 22.85 (SD = 4.43), most of whom were women (n = 5943, 70.53%). During mandatory confinement, mobility due to retail and recreation, to groceries and pharmacies, to parks, to transit stations, to workplaces were reduced by nearly 50%. In contrast, mobility to places of residence increased by nearly 20%. A reduction in mobility to workplaces was associated to less healthy eating behavior, depression and worse sleep quality. Less healthy eating behavior was also associated to decreased mobility due to recreation and retail and increased mobility to transit stations. Sense of coherence was not associated to changes on mobility. Women and youngsters more often showed depression, less healthy eating behavior, worse quality of sleep and lower sense of coherence. Conclusion: Mobility restrictions during COVID-19 pandemic has negative effects on people's mental health. Prevention and health promotion measures directed to ameliorate the effects of confinement on mental health should target risk populations including women and youngsters.