Exploring Tourists’ Willingness to Participate in Carbon Offsetting: An Integrated Behavioral Framework with the Moderating Role of Perceived Greenwashing

Understanding tourists’ willingness to participate in voluntary carbon offsetting is essential for designing sustainable tourism initiatives. This study integrates the Value–Identity–Personal Norm model, the Theory of Planned Behavior, and the Protective Action Decision Model to examine participation willingness and the moderating role of perceived greenwashing. Informed by a literature review supported by bibliometric analysis, the proposed model was tested using partial least squares structural equation modeling with 488 valid responses from domestic tourists who had visited Ho Chi Minh City, Vietnam. Survey data were collected between February and March 2026. Biospheric values positively predicted environmental self-identity, which was positively associated with personal norms, subjective norms, and perceived behavioral control. Personal norms and perceived behavioral control positively predicted both protective behavior perceptions and stakeholder perceptions, whereas subjective norms significantly predicted only protective behavior perceptions. Personal norms (β = 0.548) and protective behavior perceptions (β = 0.189) positively predicted willingness to participate, while stakeholder perceptions had no statistically significant direct effect (β = 0.050). Perceived greenwashing weakened the relationships of personal norms (β = −0.374) and protective behavior perceptions (β = −0.337) with participation willingness, but its interaction with stakeholder perceptions was not significant (β = 0.023). The model explained 80.5% of the variance in willingness to participate. These findings highlight moral motivation and perceived action effectiveness as important correlates of participation willingness and supporting transparent, verifiable communication about carbon-offsetting initiatives.