A proxy-report from the main caregiver was used to assess children’s movement behaviors (physical activity, screen time, and sleeping). Caregivers were asked to provide the time (in hours and minutes) spent by the child on each of the movement behaviors before and during the COVID-19 pandemic. Sleep quality was assessed with a Likert scale (1 to 7; a higher score indicated better quality). The survey was piloted in a small sample before the official launch to optimize readability, length, and pertinence of the questions. The questions regarding movement behaviors are included as a Supplementary File S1. The questions included in the study were based on those included in the International Study of Movement Behaviors in the Early Years (SUNRISE, www.sunrise-study.com) [10,11], but adaptations were made to capture the potential changes during the COVID-19 pandemic. Unpublished data from pilot studies in several countries assessed the concurrent validity of the questions for measuring time spent in total physical activity (TPA) and moderate-to-vigorous physical activity (MVPA) compared with ActiGraph GT3x accelerometers (ActiGraph, Pensacola, FL, USA) have shown significant but low correlations with both TPA (r = 0.14; p = 0.003) and MVPA (r = 0.16; p = 0.002), which is comparable with other proxy-report tools in this age group [12].