Background: This study aimed to examine the relationships between anthropometric characteristics and physical fitness performance among adolescent male football academy players in Bayelsa State, Nigeria. Understanding these associations could inform player development and training strategies in youth football. Methods: A cross-sectional analytical design was used to assess 20 male football players aged 15–25 years. Anthropometric variables measured included height (170.62 ± 3.16 cm), weight (62.95 ± 1.92 kg), waist-hip ratio (0.83 ± 0.01), body fat (%), and limb lengths. Fitness attributes evaluated were speed (40-m sprint), agility (Illinois agility test), endurance (Yo-Yo test), flexibility (sit-and-reach), core strength (plank test), and power (standing long jump). VO₂max was estimated using the Siri equation, with Body Density derived from the Jackson and Pollock 3-site formula. Results: The players demonstrated moderate agility (17.87 ± 0.20 sec), sprint speed (5.71 ± 0.06 sec), and VO₂max (35.25 ± 6.12 mL/kg/min). Notably, goalkeepers’ height and VO₂max were perfectly correlated (r = 1.000, p = 0.008), and lower limb length significantly correlated with VO₂max (r = 1.000, p = 0.030). Midfielders' lower limb length strongly predicted sprint speed (r = 0.886, p = 0.019). Other correlations across positions were weak or not statistically significant. Conclusion: Anthropometric traits, particularly limb lengths and height, significantly influence select aspects of physical fitness in football players, varying by playing position. These findings support tailored conditioning programs based on player morphology.