This paper identifies which information about tourists serves as the best predictor of their pro-environmental behavior at home and on vacation. If a small set of predictors can be identified, the tourism industry would be able to use them to focus attention on attracting tourists with smaller environmental footprints. Results from a survey asking respondents about pro-environmental behavior in their role as residents and tourists indicate that environmental concern, altruism, feeling morally obliged to behave environmentally friendly, age and regional identity are the best predictors of the segment of people who behave in an environmentally friendly way at home. Income levels and moral obligation best predict membership of the segment of environmentally friendly tourists. The two segments overlap, differences between them are due to the fact that, at home, people can create the infrastructure they require to behave environmentally friendly. On vacation they need to adjust to the infrastructure provided, which can act as a barrier to pro-environmental behavior. Results have direct practical implications, highlighting the value of demand-side approaches to environmentally sustainable tourism for protected areas, both urban and rural, such as focusing on those market segments that have the highest intrinsic inclination to protect the environment.