This study evaluated changes in markers of acid-base balance that occurred during simulated soccer match-play. Sixteen academy soccer players participated in a soccer match simulation (SMS) that consisted of 90 min of soccer-specific exercise with skills throughout. Blood samples were obtained before exercise (pre-exercise), and every 15-min during the simulation (15, 30, 45, 60, 75 and 90-min), and 10 min into the half-time break (half-time). Blood lactate concentrations were elevated throughout exercise (Pre exercise: 1.5 ± 0.12 mmol·L; 90 min: 6.1 ± 0.7 mmol·L, time effect: P0.05). This is the first study to provide data concerning the acid-base balance of familiarized soccer players during exercise that simulates soccer match-play. These findings suggest that: (1) blood pH is reduced during soccer-specific exercise, and (2) although buffering capacity is reduced throughout exercise, it returns to normal during half-time. Further research is warranted to develop interventions that can maintain acid-base balance throughout the full duration of a soccer match.