Sport tourism has become an increasingly popular global phenomenon, merging the allure of sporting events with the adventure of travel. Given the scale of such events and the transient spike in population they induce, it is crucial to consider sustainable practices, particularly in choosing accommodations. Green accommodations emerge as a key solution to mitigate the environmental footprint associated with sport tourism. This study investigates the behaviour of sports fans in selecting green accommodations, highlighting the increasing preference for environmentally responsible travel options in the context of sport tourism. Following the Theory of Planned Behaviour, this research assesses how attitudes, subjective norms, and perceived behavioural control influence fans’ decisions towards eco-friendly lodging. Data were collected from an open questionnaire distributed across diverse digital platforms in Italy. The online survey included questions aimed at investigating fans’ preferences and behaviours in selecting green accommodations. Key findings reveal that, while environmental sustainability is not always the primary factor in accommodation choice, there is a notable consciousness towards eco-friendly living among sports tourists. However, the booking of green accommodations often falls short of initial intentions due to factors like limited availability, higher costs, and insufficient information. This study proposes strategies for event organisers and policymakers to bridge this intention-behaviour gap, such as enhancing the visibility of green accommodations and offering incentives to promote sustainable choices. This research contributes to a deeper understanding of consumers’ behaviour in sustainable tourism and underscores the need for integrated efforts to facilitate more environmentally conscious decisions in sport-related travel.