One of the major challenges for the tourism sector is enacting sustainable behaviours. A key strategy for hoteliers is developing persuasive messages, with the goal of encouraging guests’ voluntary participation in green programmes. Through the lens of prospect theory and construal level theory, the present study investigates to what extent a loss or gain-framed message influences recycling of hotel guests via a field and a laboratory experiment. The field experiment tests the moderating effect of message construal level (concrete or abstract) on the message frame that activate pro-environmental behaviour, while the laboratory study delves further into the mechanism by showing that perceived self-efficacy is the mechanism behind the activation of these behaviours. The findings from both studies suggest that hotel guests are more likely to engage in recycling behaviour when a concrete message is paired with a loss-framed message, because of a greater perceived self-efficacy. These results help to understand the theoretical psychological mechanisms and offer managerial implications for operators on how to engage guests to be active partners in sustainable tourism behaviours.