This study analyzed training loads of youth soccer players and examined the influence of match-related contextual variables in internal training load and fatigue. A secondary aim was to investigate the variability of these parameters throughout the season. Thirteen highly trained under-19 players (18.6 ± 0.5 years) were followed during one season. Training load (daily) and fatigue scores (weekly) were assessed using rate of perceived exertion and a short questionnaire, respectively. Higher weekly training loads were reported after a defeat or draw compared to a win (2,342 ± 987 and 2,395 ± 613 vs. 1,877 ± 392 AU; p ≤ 0.05; d = 0.30-0.45). Weekly training loads were higher after playing an away match than after a home match (2,493 ± 821 vs. 2,153 ± 577 AU; p ≤ 0.05; d = 0.23). Within training sessions, the coefficients of variation for internal training load ranged from 5 to 72%. Throughout the season, the coefficients of variation for weekly training loads and fatigue scores ranged from 29 to 49% and 18 to 44%, respectively. Weekly training load decreased as the season progressed (p < 0.001); no changes were detected for the fatigue score. In conclusion, the large variation in internal training load within a session and its sensitivity to initial and subsequent match conditions underline the need for a more individualized approach. These findings and the stability of the fatigue scores throughout the season may indicate that highly trained players modulate their pace during training.