Background: Sun exposure has positive and negative effects on health, yet little is known about the sun exposure behaviour of UK adolescents, including those more prone or less prone to sunburn. Objective: To examine sun exposure behaviour of UK white Caucasian adolescents including time spent outdoors, holiday behaviour, use of sunscreen and clothing, with assessment for differences between sun-reactive skin type groups. Methods: White Caucasian adolescents (12-15 years) attending schools in Greater Manchester completed a two-page questionnaire to assess sun exposure and photoprotective behaviour. Results: A total of 133 adolescents (median age 13.4 years; 39% skin type I/II, 61% skin type III/IV) completed the questionnaire. In summer, adolescents spent significantly longer outdoors at weekends (median 4 h/day, range 0.25-10) than on weekdays (2, 0.25-6; P <0.0001). When at home in the UK during summer, 44% reported never wearing sunscreen compared to just 1% when on a sunny holiday. Sunscreen use was also greater (frequency/coverage) when on a sunny holiday than at home in the UK summer (P <0.0001). Adolescents of skin types I/II (easy burning) spent significantly less time outdoors than skin types III/IV (easy tanning) on summer weekends (P <0.001), summer weekdays (P <0.05) and on a sunny holiday (P = 0.001). Furthermore, skin types I/II reported greater sunscreen use during summer in the UK and on sunny holiday (both P <0.01), and wore clothing covering a greater skin area on a sunny holiday (P <0.01) than skin types III/IV. There was no difference in sun exposure behaviour/protection between males and females. Conclusion: The greater sun-protective measures reported by adolescents of sun-reactive skin type group I/II than III/IV suggest those who burn more easily are aware of the greater need to protect their skin. However, use of sunscreen during the UK summer is low and may need more effective promotion in adolescents. © 2014 European Academy of Dermatology and Venereology.