Tourist behavior has a critical impact on the environmental sustainability of tourism. The hedonic nature of tourism and lack of an economic incentive make tourist behavior particularly hard to change. Making tourists behave more environmentally friendly would have substantial environmental benefits. This is the aim of the present study. Three alternative approaches are tested. The most successful approach—based on sharing monetary savings with guests—leads to a 42 percent change in one specific tourist behavior with negative environmental consequences. This new sharing-based approach significantly outperforms current approaches of increasing awareness of environmental consequences and of tourist ability to make a change. Tourism businesses should consider replacing current appeals with sharing-based schemes.