A key assumption in linguistic anthropology and sociolinguistics has traditionally been that interaction within communities tends to proceed on the basis of some degree of shared understanding of social and linguistic norms. However, in transient multilingual communities, defined here as social configurations where people from diverse sociocultural and linguistic backgrounds come together (physically or otherwise) for a limited period of time around a shared activity, such shared assumptions cannot be assumed to be in place a priori. By examining the social and linguistic processes that characterize transient communities, researchers are invited to analyze and theorize meaning-making in ways that hold the potential to enrich current work at the interface between sociolinguistics and linguistic anthropology. The article aims to take a first step in this direction by offering a definition and a discussion of the notion of transient multilingual communities, exemplified by data from an international student community in Denmark, and by discussing some of the general methodological challenges and opportunities involved in research that focuses on transient multilingual communities. The article is concluded by a brief discussion of how the notion of transient communities may be utilized in a research agenda concerned with sociolinguistic change.