Objective: This study examined the associations between body composition and physical performance in U13 and U15 volleyball players. Methods: A total of 67 female athletes participated, distributed into U13 (n = 35) and U15 (n = 32) categories. Body weight, body fat percentage, skeletal muscle mass (SMM), and body mass index (BMI) were assessed, along with maximal handgrip strength (HGS), Abalakov jump (ABK), and standing long jump (SLJ). Spearman’s rho correlations were calculated by category, with 95% bootstrap confidence intervals based on 5000 resamples and Benjamini–Hochberg adjustment for 24 comparisons. Results: In U13, SMM was associated with HGS (rs = 0.750; q < 0.001), body fat percentage with ABK jump (rs = −0.496; q = 0.020), body weight with handgrip strength (rs = 0.430; q = 0.043), and body mass index with ABK jump (rs = −0.425; q = 0.043). In U15, SMM was associated with HGS (rs = 0.705; q < 0.001), while body fat percentage was associated with ABK jump (rs = −0.437; q = 0.043) and standing long jump (rs = −0.446; q = 0.043). Conclusions: These associations were specific to the variable, test, and age category analyzed and should be considered exploratory. Given the cross-sectional design and sample characteristics, the findings do not support causal inference, individualized training prescriptions, or conclusions that specific body composition profiles optimize physical performance. Longitudinal studies are needed to confirm these findings.