This study analysed how students’ mobile phones and Snapchat are adapted to and participate in the classroom. Insights from the actor network theory were used to discuss the interconnections between students, mobile phones, Snapchat, desks, and plenary teaching. We applied video analysis to examine the minute details of unfolding sociomaterial practices. The data, which was produced in a Finnish upper secondary school in 2015–2016, is a composition of ethnographic classroom video material and screen-capture video recordings from students’ smartphones. In this study, we asked how the presence of mobile phones and Snapchat become possible in the relatively restricted pedagogical space of plenary teaching. The analysis yielded two important findings. First, students use effort to adapt Snapchat to the demands of the ongoing plenary teaching. Second, the analysis demonstrates the flexibility of the mobile phone–Snapchat entanglement that plays a crucial role in its adaptation.