Modern cricket increasingly demands repeated high-intensity efforts interspersed with low-intensity activity over long durations, making aerobic fitness a foundational quality even at junior levels. This study examined the impact of an eight-week sub-maximal aerobic training programme on selected body composition, physiological and performance variables among Under-14 cricketers. Methods: Thirty male cricketers (N=30), aged 12-14 years, registered with district-level junior cricket academies, were selected through purposive sampling and randomly assigned to an Experimental Group (sub-maximal aerobic training, n=15) and a Control Group (regular cricket coaching only, n=15). The experimental group undertook sub-maximal continuous and interval running at 60-75% of age-predicted maximum heart rate, three sessions per week for eight weeks, in addition to routine skill training. Body weight, Body Mass Index (BMI) and percentage body fat represented body composition; resting heart rate, VO2max (estimated via the 20-m multistage shuttle run/beep test) and vital capacity represented physiological variables; and 30-yard sprint, Yo-Yo Intermittent Recovery Test level and beep test stage represented performance variables. Pre- and post-test data were analysed using paired and independent sample t-tests at the 0.05 level of significance. Results: The experimental group showed statistically significant improvements across all nine variables (p<0.05), with the largest relative changes observed in Yo-Yo Intermittent Recovery performance (16.4%), beep test stage (19.4%) and percentage body fat reduction (15.2%), while the control group showed negligible, non-significant change. Conclusion: An eight-week sub-maximal aerobic training protocol produces meaningful, favourable adaptations in body composition, cardio-respiratory efficiency and cricket-specific performance capacities in Under-14 cricketers without imposing excessive physiological strain, supporting its inclusion as a safe, age-appropriate conditioning modality in junior cricket programmes.