This study investigated how the experience of a multilingual and multimodal English as a lingua franca (ELF) online intercultural exchange (OIE) influenced Taiwanese university students’ linguistic identities. Data was drawn from 26 Taiwanese students who had 10 weekly one-hour video live-chats with 18 Japanese students in 2 semesters. Taiwanese participants were interviewed on their language use and issues related to identities before, during, and after the exchange. Students’ language use patterns in the OIE and reflections on the OIE were also analyzed. Interviews revealed that the multilingual ELF experience had a liberating and empowering effect for students’ English use. In multimodal communication, they felt more comfortable using English together with other languages, evidenced by increasing productions of code-mixing utterances in later weeks. However, the anxiety of using Japanese with a native Japanese speaker still persisted. In particular, the native-speaker (NS)–nonnative-speaker (NNS) interactions constrained them to pay more attention to form and accuracy, which positioned both Taiwanese and Japanese students as either native speakers or deficient nonnative language learners.