Social media influencers have become increasingly important in shaping consumer behavior in digital tourism environments, and their growing role has transformed how travelers search for information, evaluate destinations, and make international travel decisions. Nevertheless, the sequential roles of Fear of Missing Out (FOMO) and trust in Social Media Influencers remain insufficiently explored within a unified theoretical framework. To address this gap, this study aims to examine the effects of social media influencer characteristics on international travel decisions by investigating the mediating roles of Fear of Missing Out (FOMO) and trust in Social Media Influencers within the Stimulus–Organism–Response (S-O-R) framework. To examine the proposed model, a quantitative research design was adopted using an online questionnaire administered to 739 participants from Generations Y and Z. The proposed model and hypotheses were tested using covariance-based structural equation modeling (CB-SEM) with IBM SPSS and AMOS. The findings indicate that influencer characteristics significantly influenced FOMO, trust in Social Media Influencers, and international travel decisions. The results also confirmed the mediating roles of FOMO and trust in Social Media Influencers, as well as their sequential mediating effect in explaining how influencer characteristics shape international travel decisions.