In this study, we examined the effects of lactate threshold bicycle exercise in cold water with lower muscle temperature on skeletal muscle oxygenation and glycolytic metabolism. Eight subjects in each water temperature condition (15 and 33°C) conducted 30-min lower-body water immersion followed by 30-min underwater bicycle exercise. As a result, tissue hypoxia was observed in the skeletal muscle oxygenation during the exercise performed with decreased muscle temperature, and significantly higher blood lactate concentration and respiratory exchange ratio would indicate an increase in glycolytic metabolism.