This study examined children's adherence to the Singapore Integrated 24-Hour Activity Guidelines for Early Childhood in infants, toddlers and preschoolers aged 0-6 years. A total of 901 caregivers, comprising 219 infants, 379 toddlers, and 303 preschoolers, provided information regarding their children's physical activity (PA), screen viewing time (SVT), and sleep durations on both weekdays and weekends. Meeting the 24-hour integrated activity guidelines was defined as follows: for infants ≥ 30 minutes per day of tummy time or floor-based play; zero SVT; total sleep of 14-17 hours per day for ages 0-3 months, 12-16 hours per day for ages 4-11 months; for toddlers ≥ 180 minutes of total PA per day; zero SVT under 2 years; <1 hour for ages 2 to less than 3 years; and a total sleep of 11-14 hours per day; for preschoolers ≥ 180 minutes of total PA per day; SVT <1 hour per day; total sleep of 10-13 hours per day for those aged 3-5 years, and 10-11 hours per day for 6-year-olds. Chi-squared tests were used to examine the differences in guideline adherence between weekdays and weekends. Compared to weekdays, during weekends there was a higher proportion of toddlers and preschoolers adhering to the PA guidelines (68.9% vs 50.1%; 78.9% vs 55.4%, respectively, p<0.05), and a lower proportion of toddlers adhering to SVT (38.8% vs 21.8%; p = 0.001). There was a declining adherence to all three activity guidelines as age groups progressed from infants (44.7%) to toddlers (15.8%) and then to preschoolers (9.4%). Concurrently, there was a decrease in adherence to SVT recommendations across the age groups, with adherence rates being highest among infants (83.1%), followed by toddlers (15.8%), and preschoolers (9.4%). Decreasing compliance with all three guidelines, coupled with a corresponding decline in adherence to SVT guidelines as children transition from toddlerhood to preschool age, is a cause for concern. This underscores the need for proactive efforts to educate caregivers about reducing or eliminating SVT among infants and young children.