This article examines personality and participation in an online intercultural exchange (OIE) between 57 university students in Japan (n = 28) and Taiwan (n = 29). The two-month OIE used Facebook (FB) as the medium of communication. During the online exchange, participants communicated linguistically using English as their common language and para-linguistically through photos, videos, and emoticons. The revised version of the 60-item HEXACO personality inventory was used to assess personality traits and to compare those traits with participation as measured by a FB participation rubric created for this study. From the data two themes emerged: 1) overall participation rates were high; 2) participation positively correlated with the personality item Modesty and negatively with the items Sincerity and Organization. These results suggest that a degree of modest-insincerity may be natural for student engagement in online social interaction and that the asynchronous nature of the exchange suits students who favor less structured communication activities. One of the implications of this research is that, with the required coaching and support, students can develop the necessary skills to successfully partake in OIEs.