Session ratings of perceived exertion (sRPE) are a popular tool for monitoring exercise intensity across a range of sports. Despite this, little is known regarding the application of sRPE to rowing ergometry. We therefore aimed to explore the validity of sRPE for monitoring training intensity during indoor rowing training. A thirty-six-year-old, female, indoor rower was monitored over a sixteen-week training period; prior to the British and World Indoor Rowing Championships (2nd place, 30–39 year heavyweight). Rowing training could be classified as: Maximum Effort Free Stroke Rate (MaxFree; n=37), Maximum Effort Capped Stroke Rate (MaxCapped; n=9), Oxygen Utilisation 1 (UT1; n=13) and 2 (UT2; n=23), or Recovery (n=32). Throughout each training session, heart rate and a range of ergometer-derived measures were monitored continuously. Approximately 30 minutes after each training session, the athlete recorded a global sRPE (arbitrary units; AU) via the centiMax (CR100®) scale. The mean (±SD) sRPE scores for each training mode were: 75±17 for MaxFree, 64±14 for MaxCapped, 50±15 for UT1, 31±9 for UT2 and 28±14 for Recovery. The differences in sRPE between these five training modes ranged from possibly to most likely substantial. Session RPE correlations were most likely very large with mean percentage of maximal heart rate (%HRmax; r=0.83; ±90% confidence limits 0.07), very likely very large with mean 500 m split time (−0.79; ±0.08), likely very large with normalized power output (0.77; ±0.07), and possibly very large with work (kilojoules) per minute (0.72; ±0.08). Regression analysis revealed that 80% of the adjusted variance in sRPE could be explained by the combination of mean %HRmax, mean 500 m split time, normalized power output and work per minute (SEE=10 AU); with the strongest predictor variable being mean %HRmax (partial r=0.61; ±0.16, likely large). Session RPE are able to discriminate between training modes of different physiological intensities and are associated with a range of objective internal and external measures of intensity during rowing ergometry. These findings provide new evidence to support the use of sRPE as a tool for monitoring and prescribing training with indoor rowing athletes.