This study aims to provide information to improve the performance of athletes comparing the effects of carbohydrate–electrolyte intake before and during exercise on metabolism and performance in soccer players. The study had a single-blind cross-over design. Drust’s protocol is a soccer-specific intermittent exercise test. The carbohydrate–electrolyte intake experiments were divided into three timings: first, pre-exercise; second, half-time; and third, mixed. Eight participants were included in the data analysis (age: 21.32 ± 1.19 years; BMI: 22.69 ± 1.91 kg/m²; height: 176.5 ± 7.52 cm; weight: 69.5 ± 9.18 kg; V_max: 16.75 0.71 km/h). The results of the mixed test showed a significantly lower respiratory exchange ratio than those of the placebo and half-time tests (p < 0.05). The mixed test showed significantly more fat oxidation than the half-time test (p < 0.05). The running times are placebo (422.13 ± 133.44 s) and mixed (677.38 ± 217.75 s), and the distances are placebo (1577.25 ± 517.02 m) and mixed (2530.00 ± 832.71 m) (p < 0.05). The mixed test showed a significantly lower rating of perceived exertion than the placebo test (p < 0.05). Carbohydrate oxidation and heart rate showed no significant differences between the experiments (p > 0.05). The exercise protocol in this study showed the metabolic response of soccer players to intermittent high-intensity exercise and subsequent endurance exercise. In conclusion, it can be seen that the intake of carbohydrate–electrolytes improves the performance of soccer players, and the effect varies depending on the timing of carbohydrate–electrolyte intake.