Purpose <p>This study investigated the effects of pre-cooling and cooling breaks on thermoregulatory, hydration and running responses in football (soccer) players in moderate and hot temperatures.</p> Methods <p>Forty male youth footballers participated in at least two of four matches, during which core body temperature (<i>T</i>_core), heart rate (HR), match running, hydration and perceptual responses were measured. Cooling breaks (CBs), consisting of ice-cold towels and drinks, were compared to drinking breaks (DBs), consisting of passive rest and a temperate drink, applied at the same timeframes. Both were used as pre-cooling for 10&#xa0;min before the warm-up, before the pre-match, during half-time and during additional 3-min cooling breaks at the 25th minute of each half. Initially, 20 players performed two crossover matches in 25&#xa0;°C wet-bulb globe temperature (WBGT) receiving cooling (CB₂₅) and drinking (DB₂₅). A second group of 20 players played a regular match in 25&#xa0;°C WBGT with no breaks (NB₂₅) and then a match in 33&#xa0;°C WBGT during which they received either cooling (CB₃₃) or drinking breaks (DB₃₃).</p> Results <p>In CB₂₅, players felt cooler (<i>p</i> &lt; 0.001) and less fatigued (<i>p</i> &lt; 0.045) than in DB₂₅, without differences in match running (<i>p</i> &gt; 0.20), HR_mean (<i>p</i> &gt; 0.35) or <i>T</i>_core (<i>p</i> &gt; 0.09). Players in CB₂₅ sweated less (<i>p</i> = 0.005) and drank less (<i>p</i> = 0.002), resulting in no significant difference in body mass loss compared to DB₂₅. In CB₃₃, players had lower HR_mean (<i>p</i> = 0.007), similar total distance (<i>p</i> = 0.21), lower peak <i>T</i>_core (<i>p</i> &lt; 0.001) and lower body mass loss (<i>p</i> = 0.007) compared to NB₂₅. In DB₃₃, players reduced moderate (12–18&#xa0;km/h; <i>p</i> = 0.007) and high-speed running distance (18–24&#xa0;km/h; p = 0.002) but had similar peak <i>T</i>_core (<i>p</i> = 0.71) and body mass loss (<i>p</i> = 0.95) to that in NB₂₅.</p> Conclusions <p>In general, high <i>T</i>_core values and body mass losses were observed even when playing in moderate heat. Both drinking and cooling breaks attenuated the continuous <i>T</i>_core rise, but using cooling also improved player perceptions in moderate temperatures. In hotter temperatures, cooling breaks further lowered <i>T</i>_core and body mass loss compared to using only drinking breaks.</p> Trial Regsistry <p>German Clinical Trials Register: DRKS00032208.</p>