Objective: To determine the energy expenditure and time spent on physical activities in Costa Rican overweight or obese schoolchildren in free-living conditions. Methodology: Participants were 31 boys and 13 girls aged 6 to 9 years old (7.6 ± 1.03 years) with overweight or obesity; nutritional status was established by BMI. The variables of the study were: anthropometric, body fat percentage (%BF), total energy expenditure product of physical activity performed during the day (EEPA daily total), plus the energy expenditure by physical activity (EEPA), and time spent on physical activity (TPA), both variables in sedentary condition, light, moderate and vigorous intensity estimated by the Actiheart accelerometer. Results: Size and %BF were significantly higher in girls (126.8 ± 5.9 cm, 34.0 ± 6.4% BF) than in boys (123.0 ± 5.4 cm, 25.2 ± 6.9% BF). Boys recorded a daily total EEPA of 824 ± 228.1 kcal / day, moderate + vigorous EEPA 285.6 ± 131.7 kcal / day and a moderate + vigorous TPA 147.0 ± 66.6 min; significantly higher (P <0.05) than girls 395 ± 144.4 kcal / day, 139.6 ± 90.1 kcal / day and 75.6 ± 43.2 min respectively . Conclusions: Schoolchildren perform over 60 min/day moderate to vigorous intensity PA recommended, however; the EEPA moderate to vigorous intensity does not meet the minimum recommendation of 300 kcal / day for weight reduction. This could be one of the causes for overweight schoolchildren.