This study investigated the effect of completing additional warm-up strategies in the transition phase between the pool warm up and the start of a race on elite sprint swimming performance. Twenty-five elite swimmers (12 men, 20 ± 3 years; 13 women, 20 ± 2 years, performance standard ~807 FINA2014 points) completed a standardised pool warm up followed by a 30-min transition phase and a 100-m freestyle time trial. During the transition phase, swimmers wore a tracksuit jacket with integrated heating elements and performed a dry land-based exercise routine (Combo), or a conventional tracksuit and remained seated (Control). Start (1.5% ± 1.0%, P = 0.02; mean ± 90% confidence limits) and 100-m time trial (0.8% ± 0.4%, P < 0.01) performances were improved in Combo. Core temperature declined less (-0.2°C ± 0.1°C versus -0.5°C ± 0.1°C, P = 0.02) during the transition phase and total local (trapezius) haemoglobin concentration was greater before the time trial in Combo (81 µM ± 25 µM versus 30 µM ± 18 µM, P < 0.01; mean ± standard deviation) than in Control. Combining swimmers traditional pool warm up with passive heating via heated jackets and completion of dry land-based exercises in the transition phase improves elite sprint swimming performance by ~0.8%.