Social media platforms are now prevalent in tourism literature and have the potential to influence tourists’ decision-making by impacting the process of their destination image (DI) formation. The study aims to investigate the online DI formation process by simultaneously incorporating three pivotal constructs—involvement, source credibility, and authenticity—in the context of social media platforms. The study employed a mixed-method design. Results indicate that: (1) authenticity and source credibility both have positive influence on the formation of DI, demonstrating it as an antecedent of the tourists’ intention to visit; (2) tourists’ perceived authenticity has a direct positive impact on the intention to visit; (3) tourists’ involvement might not be a significant factor in the formation of online DI. This study highlights the factors affecting tourists’ perception of and intention towards selecting a tourism destination in the context of social media platforms.