We aimed to determine whether the physical and physiological superiority of early-maturing rowing athletes, observed at ages 12–13 years, over that of their late-maturing counterparts observed at the same ages, still persists at 17–18 years of age, when all adolescent athletes are expected to have completed pubertal development. We hypothesized that this superiority of early maturers would not be observed at reassessment, as late maturers would have likely “caught up” with their early-maturing peers. Twenty-one male rowers were assessed at age 12.8 ± 0.5 years and again at 17.5 ± 0.5 years (mean ± SD). They were divided into groups of early-maturing and late-maturing rowing athletes based on Tanner's sexual maturity ratings. A two-way repeated-measures MANOVA followed by a series of ANOVAs with one within-subject factor (time) and one between-subject factor (group) indicated significant (P≤0.003) within-subject and between-subjects main effects for lean body mass (LBM), maximal oxygen uptake (Symbol), and mean power (MP). The group × time interaction effects were significant for LBM (P=0.003),Symbol(P=0.004), but not for MP (P=0.171). Over 5 years, early-maturers' advantage dwindled in terms of LBM (+38% to +9%),Symbol(+47% to +9%), and MP (+76% to +15%); however, these differences may still be considered practically relevant. The proposed hypothesis was not supported.