Social media offers a platform for travellers to share their information about experiences and opinions about their vacation trips. This information is, in turn, used by travellers in organizing and taking vacation trips. This research provides empirical evidences to test theoretical model explaining the use of social media by travellers during their vacation trips. Three theoretical antecedents were identified from previous literature including benefits, costs, and incentives of using social media that explain use of social media in organizing and taking vacation trips. A total of 394 questionnaires were collected from travellers who visited Thailand. Rather asking respondent to think back about what they did during their trips, a prospective approach of data collection employed in this research would help increase the degree of validity. The results showed that benefits and incentives of using social media were two main significant antecedents of the social media use. Travelling social media sites need to address benefits of using social media and offer incentives to users.