Summary Background Skin cancer is the most commonly diagnosed cancer in the U.K. With the aim of reducing, and hopefully reversing, the year-on-year rise in skin cancer incidence, SunSmart, the U.K.’s national skin cancer prevention campaign, has been hosted by Cancer Research UK since 2003. Objectives To gather data about how much time visitors to the SunSmart website spend in the sun, their preferred forms of sun protection and their use of tools such as sun-reactive skin type and ultraviolet (UV) index. Methods The study was carried out using a quantitative on-line survey hosted by Cancer Research UK’s SunSmart website ( http://www.sunsmart.org.uk) between May and September 2007. Results Just over 2000 respondents completed the survey. Young adults are more likely to experience sunburn than older adults, a factor that was found to be much more important than individual susceptibility to sunburn. Initiatives such as using the UV index to guide sun exposure and checking skin regularly for unusual changes both appeared to be associated with a lower incidence of recent sunburn. The distribution of time spent outdoors by indoor workers during summer months demonstrated clearly how important recreational exposure is in influencing the overall solar UV burden. Conclusions This on-line survey, while not entirely representative of the U.K. population, has highlighted those factors that can be effective in reducing the incidence of sunburn, and presumably skin cancer, and that messages about the secondary prevention of skin cancer clearly have some overlap with those advocating primary prevention.