Background: The purpose of this study was to investigate daily physical activity (PA) patterns of 8- to 9-year-old Irish children from socially disadvantaged areas. Methods: Children (N = 408) were asked to wear an ActiGraph accelerometer for a minimum of 4 days. Based on mean daily moderate- to vigorous-intensity PA accumulation, participants were grouped into sex-specific quartiles (Q4, most active; Q1, least active). Principal component analysis was used to identify distinct time blocks for weekdays and weekend days. Results: Overall, 213 participants (8.7 [0.5] y) met accelerometer inclusion criteria. Of these, 56.7% met the 60 minutes of moderate- to vigorous-intensity PA per day guidelines, with males statistically significantly more likely to do so than females (P < .01). Principal component analysis revealed 3 distinct time periods on weekdays and 4 distinct periods on weekends that children were active. The total difference in moderate- to vigorous-intensity PA accumulation between Q4 (most active) and Q1 (least active) was greatest in the after-school time period (male: 49 min and female: 33 min) on weekdays and in the evening time period on weekends (male: 33 min and female: 19 min). Conclusions: After-school and weekend evenings are critical “activity rich” time periods in terms of the gap between our most and least active disadvantaged children.