The COVID-19 pandemic compelled a substantial increase in telework intensity, or the amount of time that the individual habitually works outside the office. In this paper, we introduce the term telework density to describe a concurrent trend—a rise in the extent to which workers’ colleagues and family members are themselves teleworking. Drawing on the telework and time-use literatures, we argue that this dual increase in telework intensity and density presents a theoretical tension between an increase in discretionary time-use for the teleworker due to greater time spent at home, and a decrease in discretionary time-use due to greater synchronization needs from work and non-work demands. To examine this tension, we conduct an inductive study of government employees in the United Kingdom. Through 43 in-depth, semi-structured interviews, we identify time fungibility as a key factor in helping workers manage the additional constraint engendered by telework density. Time fungibility is the substitutability of units of time, allowing workers to substitute work-time with non-work time. We uncover two underlying mechanisms driving time fungibility—mutual awareness and accommodative behavior amongst colleagues; and scheduled, technologically-mediated interactions—which ensured that telework density enabled rather than constrained discretionary time-use, thus alleviating the theoretical tension between telework intensity and density. We seek to contribute to the literatures on telework, time-use, and work-life management. More proximally, our findings contribute to the conceptual toolkit of researchers examining the lasting legacy of COVID-19 on work practices.