The aim of this investigation was to determine the effect of even, negative and positive pacing on metabolic, kinematic and temporal variables during breaststroke swimming. Nine male swimmers [mean (SD): age 21 (3) years, height 178 (5) cm, body mass 77.2 (6.7) kg, 200 m-time 158.6 (13.6) s] completed a 200-m breaststroke time trial and then 72 h later three paced (even, positive, negative) 175-m breaststroke swims in random order, 48 h apart. The swimmers paced accurately in all trials. The evenly paced trial produced lower post-exercise peak blood lactate and rating of perceived exertion values compared to the positively paced trial (P < 0.05). Peak oxygen uptake was not significantly different between trials (P > 0.05). Heart rate immediately following exercise was lower in the negatively paced trial (P < 0.05) than the other paced trials. Stroke rates were lower during the first half of the evenly and negatively paced trials compared to the positively paced trial (P < 0.01), but no differences were observed between the second half of the trials. Across all trials the stroke count increased as the trials progressed (P < 0.01). Turning times were observed to be shorter during the first half of the positively paced trial compared to the other paced trials (P < 0.01). Even paced swimming appears to be less physically stressful than positively paced swimming during high intensity exercise, as indicated by a lower post-exercise blood lactate concentration, perceived exertion and variability within turning times.