The article engages with the notion of the smart prison to develop an understanding of emerging temporalities of digital technologies. The prison context serves here as a magnifying glass that makes certain contradictions and paradoxes of the digital imperative visible. Starting with a brief discussion of smart technology discourses, the article explores the temporalities of real-timeness, prediction and pre-emption that are entangled with digital technologies. Analysing the Spartan RFID tracking tool, the use of algorithms in prison administration and a mobile phone application used in Swedish probation, the article identifies a desynchronization between the temporalities of the incarcerated individuals’ lived experience and the (imagined) temporalities of the smart prison. The findings point to developments that are relevant for the smart, digital society beyond the prison walls.