Although recent years have witnessed an increasing interest in learning Chinese as a foreign language (CFL) in China and around the world, there seems to be a paucity of research into the medium of instruction (MoI) in the CFL classroom. The paper describes a study of the practice of MoI choice in the CFL classroom situated within the framework of translanguaging. Five focus group interviews and eight class observations were conducted across five universities in China. Approximately ten CFL experts and forty students who were in training to become CFL teachers participated in the research. The initial findings suggest that nowadays it is unlikely that a Chinese-only principle can be used in the multilingual and/or multinational classroom. Instead, code switching between Chinese and English was commonly found. However, due to the resource availability and linguistic complexity of a CFL classroom, these translanguaging practices also posed challenges to the language learning development. Interestingly, English was predominantly employed for explanatory and elicitation functions, whereas the choice of Chinese was made mainly for teaching and instructing purposes. While more translanguaging practice can be observed in the advanced CFL class than in the beginner’s class, the monolingual approach was still predominantly used across different levels. Despite the occurrence of translanguaging in the classroom, both CFL teachers and learners advocated for the Chinese-only principle which they believe can better assist learners in CFL acquisition. The research discusses the changing roles of student and teacher in the CFL classroom, which will offer insights to future pedagogical developments in foreign language teaching and learning.