Long-standing research has highlighted the critical role of physical and outdoor activities for children’s health and well-being. During the COVID-19 pandemic, children around the world experienced heightened stress and poor mental health, which coincided with a decrease in active play and increase in screen-based activities. This study examined how physical, outdoor, and screen-based activities impacted emotional well-being during the post-lockdown period of COVID-19. Caregiver proxy report of children’s activities and emotional well-being was collected from 190 caregivers through an online survey in February-April 2021. Overall, we observed low levels of physical and outdoor activities and high levels of screen activities in children, especially those aged 5 and older. Unadjusted models suggested that time spent in physical activity and online socializing predicted child well-being positively and negatively, respectively. However, only child age, parent-child co-play, parent stress, and family life satisfaction emerged as significant predictors of child well-being in the fully adjusted model. The findings facilitate a deeper understanding of children and youth’s outdoor engagement during the pandemic and highlight the critical role of parents and families in supporting children’s emotional well-being and healthy recreation under sustained stress and disruption.