The use of communication strategies (CSs) has been of interest on research into second language acquisition (SLA) since it can help learners to attain mutual comprehension effectively and develops understanding of interaction in SLA research. This study investigates and clarifies a wide range of CSs that learners of English and learners of Chinese use to solve language problems as well as to facilitate problem-free discourse in both text-based and video-based SCMC environments. Seven Chinese-speaking learners of English and seven English-speaking learners of Chinese were paired up as tandem (reciprocal) learning dyads in this study. Each dyad participated in four interactions, namely, text-based SCMC in English, text-based SCMC in Chinese, video-based SCMC in English and video-based SCMC in Chinese. The interaction data were analysed along with an after-task questionnaire and stimulated reflection to explore systematically and comprehensively the differences between text-based and video-based SCMC and differences between learners of English and learners of Chinese. The results showed that learners used CSs differently in text-based and video-based SCMC compared with their own performance and indicated different learning opportunities provided by these two modes of SCMC. Although the difference in language was less salient than the medium effect, learners of English and learners of Chinese tended to have their own preferences for particular CSs. When these preferences appear to reflect an appropriate communicative style in one particular culture, learners might need to raise their awareness of some strategies during intercultural communication to avoid possible misunderstanding or offence. Some possible advantages of tandem learning interaction were also identified in this study, such as the potential to develop sociocultural and intercultural competence due to the opportunity to practice culturally appropriate language use with native speakers in a social context.