Purpose: The transition into full-time training represents a key period in the development of young soccer players. Here we compared the weekly training loads (matches, field-, and resistance-training) of English Premier-League Academy soccer players from under-16 (U16), under-18 (U18) and under-23 (U23) age-groups during a training meso-cycle. Methods: Forty players (U16 n= 13, U18 n= 15 and U23 n = 12) were monitored using global navigation satellite systems and differential ratings of perceived exertion (dRPE). External load metrics were total distance, high-speed running distance, (absolute: ≥19.8km·h-1, relative: ≥87% of 30-15 final-velocity [vIFT]), sprint distance (absolute: ≥25.2km·h-1, relative: ≥80% maximal sprint speed), and dynamic stress load. Internal load metrics were dRPE training loads. Results: Other than relative sprint distance, overall weekly external training loads were substantially greater for U18 and U23s when compared with U16s (effect size range: 1.09–1.99 [moderate to large]; ±90% confidence limits ~0.45). When compared with U16s, overall internal loads were substantially greater for U18s (0.69–0.95 [moderate]; ±~0.40), but not U23s. Differences in weekly training loads between U18s and U23s were inconclusive. Conclusions: Substantial differences in training loads between elite U16 players and their older counterparts, indicates the need for planned increases in training loads in anticipation of the transition into full-time training.