Recess is a frequent target in school-based physical activity (PA) promotion research but there are challenges in assessing PA during this time period. The purpose of this study was to evaluate the reliability and validity of a recess PA recall (RPAR) instrument designed to assess total PA and time spent in moderate to vigorous PA (MVPA) during recess. One hundred twenty-five 7th and 8th-grade students (59 females), age 12–14 years, participated in the study. Activity levels were objectively monitored on Mondays using different activity monitors (Yamax Digiwalker, Biotrainer and ActiGraph). On Tuesdays, 2 RPAR self-reports were administered within 1-hr. Test-retest reliability showed ICC = 0.87 and 0.88 for total PA and time spent in MVPA, respectively. The RPAR was correlated against Yamax (r = .35), Biotrainer (r = .40 and 0.54) and ActiGraph (r = .42) to assess total PA during recess. The RPAR was also correlated against ActiGraph (r = .54) to assess time spent in MVPA during recess. Mean difference between the RPAR and ActiGraph to assess time spent in MVPA during recess was no significant (2.15 ± 3.67 min, p = .313). The RPAR showed an adequate reliability and a reasonable validity for assessing PA during the school recess in youth.