The Sustainable Development Goals are crucial in tourism, since they foster new tourist practices. These include the green label, whose presence on booking platforms reassures eco-conscious tourists. However, does this label influence their booking intentions? This study aims to answer this question by analyzing the impact of green labels on online booking intentions. Using signal theory, we explored the online booking process for sustainable hotels. The chapter uses a structural equation model (SEM) with 349 responses to assess the impact of green labels on booking intentions. Green trust and green perceived risk were tested as mediators between green label perception and booking intention, while environmental awareness was examined as a moderator of this relationship. The empirical results highlight, on the one hand, that eco-conscious tourists’ perception of the green label clearly influences their intention to book sustainable hotels online. Green labels reduce perceived risk and increase trust in the hotel’s eco-practices. Environmental awareness also plays a moderating role. In light of these results, theoretical and managerial implications are developed. Tourists are sensitive to green labels when booking sustainable hotels online. Green labels reduce perceived risk and increase trust in the hotel’s eco-practices. Environmental awareness also plays a moderating role. This study shows the importance of green labels for eco-conscious tourists. Their impact is mediated by green trust and green perceived risk and moderated by environmental awareness.