Transactive memory systems (TMS) is now an important factor in information sharing. This study adopted TMS to understand the intentions of tourists who share travel information in social media. Tourist’s information is shared either by the formal or informal types of communication. To understand their intentions in using social media, this paper concerns the three measurements employed by TMS; that is, specialization, credibility, and coordination; and the potential tourists’ perception of communication types and TMS are measured in this research model. This research employed empirical analysis using structural equation modeling upon 309 Korean users who shared travel information on social media to attain three findings. First, that the users’ perception of formal communication has a positive influence on the specialization, credibility, and coordination of social media. Second, that the perception of informal communication has a positive effect on the credibility and coordination of social media. Third, that three sub-dimensions of TMS affect intentions to share travel information, which provides us with significant theoretical and practical implications.