I studied 5 wet-suited scuba divers studied on 26 dives in the Antarctic. The median duration of dives was 29 min, during which divers were usually involved in sampling or observations for marine biology or chemistry projects. Rectal temperature (Tre) and seven skin site temperatures were measured with thermistors, and mean skin temperature (Tsk) and heat loss estimated. Divers usually heated up during changing and transport to a dive. By the end of immersion, Tsk decreased to a median of 22 degrees C, and finger temperature decreased to a median of 10 degrees C, while the median heat loss during immersion was 850 kJ. Tre below 36 degrees C was not recorded. This study shows that divers do not become clinically hypothermic, but that they are subject to severe cooling, and skin temperatures reach levels at which manual and mental impairment may occur.