BACKGROUND Sun exposure increases risk of skin cancer, especially melanoma, incidence of which continues to rise. Reported skin cancer knowledge and trends in sun care behaviours are documented in a UK region where there has been 20 years of sun-related health promotion campaigns. METHODS In 2000, 2004 and 2008, a 'care in the sun' module was included in the Northern Ireland (NI) Omnibus survey. Randomly selected subjects were asked to complete a sun-related questionnaire and proportions of respondents analysed by demographic and socio-economic factors, with differences tested using z-tests and the chi-squared test. RESULTS Around 3623 persons responded. Skin cancer knowledge was high (97%). Sun avoidance decreased with time and was lowest among younger age groups and males. Sunscreen use was high (70%), unchanged over 8 years, and more likely among younger age groups, females, those in paid employment, and those with tertiary level education. Use of sunscreen with minimum Sun Protection Factor (SPF) 15 (a campaign message) increased from 45% to 70% (P < 0.01). Skin self-examination was infrequent (8%), less common among those aged ≥65 years, males and those with only primary or secondary level education. CONCLUSIONS Messages on sunscreen use have penetrated the population well, but lower use among the unemployed suggests cost as an issue. Lack of sun avoidance in young people, especially men, poses a risk for further skin cancer increases. Low levels of reported skin self-examination in older people, men and those with lower educational attainment identify areas for further action.