Longitudinal studies evaluating the seasonal change of aerobic capacity in young soccer players of different age categories are limited. The aim of this study was to investigate the seasonal changes in the aerobic level of the youth academy players of a professional soccer team. This research study was carried out with a total of 51 soccer players in the U14, U15, U16, U17, and U18 categories of an elite soccer team. Aerobic capacities of the athletes were measured by Yo-YoIRT 1 Test. In the analyses, the normal distribution evaluations of the data were made with the Shapiro-Wilk test and the variance homogeneities were tested with the Levene’s Test. One Way ANOVA test was used to analyze all the parametric data. All statistical evaluations were performed with the help of the SPSS 21 package program. According to the Yo-YoIRT 1 test, increases or decreases were determined in the pre-season, mid-season and end-of-season evaluations. As a result, in the present study conducted to examine the seasonal changes of the young elite soccer players in the U14, U15, U16, U17, and U18 categories, Yo-YoIRT 1 values in all categories increased significantly at the end of the season when compared to the pre-season and the mid-season. U14 and U16 age groups gained increasing acceleration starting from the pre-season. However, in the U15, U17, U18 age groups, the case is that acceleration decreases in the middle of the season and increases at the end of the season. It is thought that differences can be observed in the responses to the training loads during maturation. It can be suggested that the increase at the end of the season compared to the pre-season in all groups may be due to the fact that the adaptation of the athletes to the training programs are affected by the developmental characteristics regarding the age categories over time.