This dataset contains physiological data collected from 16 elite artistic swimmers during full and segmented free duet routines. Variables include oxygen uptake (absolute and relative), heart rate (detailed by routine segment), blood lactate concentration, rating of perceived exertion, and time durations of each routine segment. The dataset is structured to allow comparisons between baseline, pre-apnea, post-apnea, and post-routine phases. It supports the analysis presented in the manuscript “Physiological responses to full and segmented duet routines in elite artistic swimmers.”