The development of new media technology facilitates interaction between people of different cultures. However, people from different cultures show different cross-cultural communication behaviors that may influence their communication efficiency, perceived communication experiences, and perceived social presence. This study aimed to explore Taiwanese students' communication behaviors and their perceived social presence in online cross-cultural communication. Nineteen English-major students participated in a 10-week online cultural communication exchange with students from Japan and Colombia. The data were collected from their online interaction postings, an after-study survey, and the teacher's observation journal. Content analysis of the postings and the teacher's observation journal were utilized to identify their online communicative behaviors. Moreover, the survey data were analyzed to examine their perceived social presence. Finally, the results of the questionnaire and interaction data were compared to identify the types of communicative behaviors favorable to social presence development. The results suggested that the Taiwanese students in this study had similar communicative behaviors and shared some with the communicators from some low-context cultures. The more types of communicative behaviors they used in online cross-cultural communication, the better they perceived social presence. Some types of communicative behaviors (e.g., using emoticons or expression symbols, using more expression types, self-disclosing more) seemed to benefit their social presence development more than others.