<p>Low-carbon travel in longevity tourism promotes sustainable lifestyles, environmental responsibility, and long-term well-being. However, limited research examines how social and cultural factors influence tourists’ low-carbon travel decisions in Thailand, creating challenges for destination managers in promoting environmentally responsible travel behavior. This study investigates the influence of destination sustainability attributes, marketing communication, social norms, cultural values, environmental attitudes, and low-carbon travel intentions on tourists’ travel decisions. Data were collected from 650 tourists visiting nature-based and wellness-oriented destinations across Thailand. Reliability and internal consistency were confirmed using Cronbach’s alpha (α = 0.79–0.87) and composite reliability (CR = 0.82–0.90), while confirmatory factor analysis validated the measurement model (AVE = 0.58–0.69). Structural Equation Modeling using SmartPLS was employed to examine direct and indirect relationships, and bootstrapping was applied to test mediation effects. The results reveal significant direct effects of destination sustainability attributes (β = 0.62, R² = 0.41) and social norms (β = 0.66, R² = 0.44) on low-carbon travel intentions. Indirect effects through marketing communication (DSA → MC → LCTI, β = 0.41) and social norms (CV → SN → LCTI, β = 0.39) indicate partial mediation. Model fit indices demonstrate strong validity and robustness (χ²/df = 2.20, CFI = 0.96, RMSEA = 0.052, SRMR = 0.043) using IBM SPSS Statistics Version 26. The findings highlight the importance of culturally informed marketing communication, sustainable destination attributes, and social norms in promoting low-carbon travel behavior. Integrating these factors can support destination planning and policy development aimed at fostering sustainable longevity tourism practices.</p>