Objective: to describe where smokers smoke outdoors, where non-smokers are exposed outdoors to secondhand smoke (SHS), and attitudes towards smoke-free outdoor areas after the implementation of national smoke-free legislation. Design: this cross-sectional study was conducted between June 2011 and March 2012 (n=1307 participants). Setting: Barcelona Participants: representative, random sample of the adult (≥16 years) population. Primary and secondary outcomes: proportion of smoking and prevalence of exposure to SHS in the various settings according to type of enclosure. Percentages of support for outdoor smoke-free policies according to smoking status. Results: smokers reported smoking outdoors most in bars and restaurants (54.8%), followed by outdoor places at work (46.8%). According to non-smokers, outdoor SHS exposure was highest at home (42.5%) and in bars and restaurants (33.5%). Among non-smoking adult students, 90% claimed exposure to SHS on university campuses. There was great support for banning smoking in the majority of outdoor areas, which was stronger among non-smokers than smokers. Over 70% of participants supported smoke-free playgrounds, school and high school courtyards, and the grounds of healthcare centres. Conclusions: extending smoking bans to selected outdoor settings should be considered in further tobacco control interventions to protect non-smokers from SHS exposure and to establish a positive model for youth. The majority of public support for some outdoor smoke-free areas suggests that it is feasible to extend smoking bans to additional outdoor settings.