During this COVID-19 pandemic, no one can deny the value of online communication. It has saved our lives by preventing us from going outdoors and becoming infected, while also facilitating achievement of various personal and professional goals. Online communication can also assist us with our academic goals, whether it is used to communicate with supervisors or with people from other lingua-cultural backgrounds to practice the language. This form of communication is emphasized in the Common European Framework of Reference for Languages (CEFR) framework, which is one of the most significant guidelines for language teaching and learning throughout the world. The present research has two aims: first, to determine the extent to which CEFR-based online intercultural communication can improve Thai students' communicative language competence, and second, to investigate Thai students' attitudes toward CEFR-based online intercultural communication and international volunteers. The results received from 15 fifth-year dual B.A. (Chinese) and B.CM. (Traditional Chinese Medicine) students and international volunteers using various research instruments revealed that Thai students could increase their communicative language competence after participating in CEFR-based intercultural communication activities. This encompassed linguistic, sociolinguistic, and pragmatic abilities that correspond to the CEFR (2001) scales. In terms of attitudes, the study indicated that, because they were more confident in their communicative language ability, they had a positive attitude toward the CEFR-based online intercultural communication activities and their international volunteers. Finally, further research on this topic should include a proper design of online communication activities as well as methods for assessing students' competency both before and after participation.