The emergence of digital technologies has opened new methods for engaging consumers, conducting focus groups, and gathering research material online. One such method is the use of smartphone-based mobile messaging platform WhatsApp, which allows real-time discussions and diary-type studies. Nevertheless, the potential of WhatsApp focus groups as a research method necessitates further exploration. This paper analyses the advantages and limitations of employing WhatsApp-based focus groups in qualitative consumer studies related to sustainable eating. Specifically, we will examine the effectiveness, interaction, and quality of research materials obtained through this method in previous studies. To carry out our study, we organized a focus group in Finland utilizing the WhatsApp-based platform with a pre-selected panel of 24 participants. The study explored barriers to sustainable food choices among so-called imperfect consumer segments. Based on our observations, mobile focus groups offer a fruitful method for studying consumer insights due to the direct and non-hierarchical communication channels they provide between participants and researchers. However, it is crucial to acknowledge that materials acquired through mobile groups may be less extensive than those obtained through traditional focus groups. Participants often rely on emojis and emoticons to convey meaning, which may pose challenges in terms of text-based coding, categorization, and software utilization. Furthermore, the fragmented nature of messages presented another challenge in analysing the collected material. Additionally, when employing WhatsApp focus groups as a method, careful preparation of the question route is necessary to ensure the production of high-quality research materials.