Background: Identifying where children spend their activity-Time may help define relevant domains for effective PA promotion and better understand the relation between PA and environment. Our study aimed to identify how boys and girls allocate their active time in the different domains. Methods: 374 children (201 girls; mean age = 11.7 years) wore an accelerometer and a GPS for 7 days. PALMS software combined data, categorized nonsedentary time and bouts of moderate-To-vigorous physical activity (MVPA). Geographical information system allocated activity into 4 domains: school, leisure, transport and home. Results: Overall, a higher proportion of time in MVPA was found in the transport domain (45.5%), school (30.5%), leisure (21.3%), and home (2.7%). Gender differences were found for the proportion of time spent across domains. Girls (54.5%) had more MVPA than boys (35.2%) in the transport domain, whereas boys spent more MVPA time in school (37.0%) and leisure (24.9%) than girls (24.7% and 18.1, respectively). Conclusions: Interventions to increase transport behavior may be relevant for children's MVPA. School is an important domain for boys PA, while for girls increasing the supportiveness of the school environment for PA should be a priority. Strategies should consider gender differences when targeting each domain.