Maximal peak power (MPP) is strongly associated with 2000 m rowing performance and is likely to become a critical predictor of success with the shift to 1500 m racing at the 2028 Olympic Games. However, no consensus exists on a standardized protocol for assessing MPP in rowing. This study examined the reliability of a 10-stroke ergometer-based MPP test in elite under-23 rowers, assessing its association with time-trial performance. Thirty-three athletes (10 females) completed 10 MPP tests across five sessions. The protocol included five lead-in strokes followed by five maximal strokes at 40 strokes per minute. As greatest MPP values were consistently obtained during the first test, the second test of each session was excluded from analyses. Mean (±SD) bias between the three experimental sessions was 1.0 (±0.4)% for males and 0.9 (±0.7)% for females. The test demonstrated near perfect between-session reliability, with intraclass correlation coefficients ranging from 0.92 to 0.99. A near perfect relationship was found between MPP and 2000 m (r = 0.93) and 1500 m (r = 0.94) ergometer performance. This protocol provides a reliable, valid, and practical tool for assessing true MPP improvements and profiling athletes within a stroke rate that mirrors contemporary on-water racing demands.