The concept of energy availability is recognized as energy expended for essential physiological processes. Accumulated research data help to set up the guideline with the concepts of Female Athletes Triad (FAT) and Relative Energy Deficiency in Sports (RED-S) model. However, it is required further scientific progresses, and one of them is studying on male athletes and in different ethnicity group. From this, we investigated energy status of Korean athletes in the present study. We recruited collegiate soccer players in Korea, and collected energy intake data from 7-days dietary records, exercise energy expenditure from heart-rate monitoring during training, non-exercise activity thermogenesis from physical activity records with accelerometer, and total energy expenditure from doubly labeled water (DLW) measurements. Also, we conducted VO₂ max test, resting energy expenditure measurement, dual-energy x-ray absorptiometry (DXA) measurement, and blood analysis to calculate energy availability and analyze the relationships. Analyzed data shows low energy availability level than cut off value (30 kcal/kgFFM/d, FFM: fat-free mass) in the subjects. Some values show relation with low energy availability, but it needs more analyzation and scientific evidences for further explanation. For the next research, we are planning to investigate Japanese collegiate soccer players applying same methods.