Background: Little is known about pre-pubescent Filipino children's involvement in moderate-to-vigorous physical activity (MVPA). There are international guidelines regarding required levels of MVPA for healthy children. Methods: This study describes participation of 11- to 12-year-olds in randomly selected public and private schools in San Juan, Metro Manila, in MVPA and sports during a school day. The Filipino-modified Physical Activity Questionnaire for Older Children (F_PAQ_C) was administered in English and Filipino. Additional data was collected on sex, age, type of school, and amount of time spent using television and computers. Children's self-assessment of physical activities (1 question in the F_PAQ_C) was correlated with their cumulative F_PAQ_C score. Results: Three hundred eighty subjects (167 boys, 213 girls) participated. Participation in MVPA varied between sex and age groups, from 56.1% to 65.0%. Fewer than 10% of participants were very active. The children were more active during physical education classes than at recess or lunch, after class, or in the evening. Walking for exercise, jumping, jogging and running, free play, and dance were most common. Boys, younger children, and private school students most commonly engaged in MVPA. Self-assessed physical activity had modest correlation (r[superscript 2]= 0.21) with cumulative F_PAQ_C score, after adjusting for sex, age, and school type. Conclusion: Most children were not physically active during the school day, except in physical education classes. To reduce the gap between recommended and current activity levels, more opportunities should be provided for preteen Filipino children to engage in MVPA during and after school. (Contains 3 tables and 1 figure.)