ABSTRACTObjectives: The purpose of this study was to examine the effects of Ramadan fasting on physical activity profile of soccer players via the satellite global positioning system during a 90-min match played in the Tropics.Methods: Thirteen trained Muslim players locomotor data were averaged over four simulated matches; where two were played in the non-fasted or control (CON) state and two in the Ramadan-fasted (RAM) state. Standardised pre-match diet were consumed at ~12:00 in CON and at ~05:30 in RAM conditions. Questionnaires on sleep hours, mood state and perceived match-readiness were also administered. Players’ training load one week prior to matches was recorded.Results: In RAM condition, players covered a lower total distance (by 12.8 ± 5.8%), and covered less distance within the moderate (22.4 ± 12.0%) and high-speed (35.5 ± 20.1%) zones (all P < 0.025). Players accomplished a lower relative speed throughout the most of the match in RAM compared to CON condition (P < 0.008). Blood glucose, blood lactate and heart rate of the players during match in RAM and CON conditions were equivalent (all P > 0.05), although ratings of perceived exertion were higher before, during and post-match in the RAM vs. CON conditions (P > 0.05).Conclusions: Players’ physical activity profile during a soccer game was adversely affected by Ramadan fasting and this negative impact was already observed in the initial stages of the match.