There are few practical methods available for evaluating training loads (TL) during swimming. The purpose of this study was to examine the ecological validity of the session-rating of perceived exertion (RPE) method for quantifying internal TL in competitive swimmers using heart rate (HR)-based methods and distance as criterion measures. This study also examined the correspondence between athlete and coach perceptions of internal TL using the session-RPE method. Twelve (six male, six female) well-trained swimmers (mean +/- SD: age 22.3 +/- 3.1 years, weight 71.8 +/- 11.6 kg, height 175.0 +/- 9.0 cm) participated in this study. All subjects completed a swimming step test to evaluate individual HR zones and blood lactate profile before undertaking 20 swim training sessions where RPE, HR, and distance covered were recorded. Training load was then calculated for each session using the session-RPE, HR-based methods, and session distance. The session-RPE scores were correlated to HR-based methods for measuring internal TL as well as training distance for each swimmer. All individual correlations between session-RPE, HR-based methods (r = 0.55-0.94; p < 0.05), and distance measures (r = 0.37-0.81; p < 0.05) were significant. Two-way ANOVA showed that there was a significant interaction for training intensity x coach-athlete perception, indicating that coach RPE was lower than athlete RPE for low-intensity sessions and higher than athlete RPE at high-intensity sessions. The results of this study suggest that session-RPE may provide a practical, noninvasive method for quantifying internal TL in competitive swimmers.