Townsville, in Queensland, Australia, experiences very high levels of ambient solar ultraviolet radiation (UVR) throughout the year and has a predominantly white population which is prone to developing skin cancer. The UVR exposure of 1-year-old and 2 1/2-year-old children raised in Townsville was measured using UVR-sensitive polysulphone film badges. In two separate exposure studies undertaken for 7 days in October 1995 and 5 days in April 1997, exposure at the chest and shoulder for each subject was determined. The chest exposures for the 1-year-olds were significantly higher at weekends than on weekdays, whereas for the 2 1/2-year-old children the shoulder exposures were significantly higher at weekends than on weekdays. The median daily total exposure for 1-year-old infants was 0.4 SED (standard erythemal dose) for the chest and 0.4 SED for the shoulder. The median daily total exposure for 2 1/2-year-olds was 0.6 SED for the chest and 0.9 SED for the shoulder. Although the median daily total exposures were comparatively low, the maximum values for the chest and shoulder were 6.5 SED and 2.4 SED, respectively, for the 1-year-old infants, and 20.6 SED and 8.4 SED, respectively, for the 2 1/2-year-olds. While the 2 1/2-year-old children spent most of their time outside between 9 am and 4 pm, the 1-year-old infants spent more time outside before 9 am and after 4 pm. Exposure increases with age in early childhood. Increased mobility and a greater tendency to play outdoors is likely to account for the higher exposure levels in 2 1/2-year-old children, compared to 1-year-old infants.