BackgroundAs e-scooters have become common modes of transportations in urban environments, riding e-scooters has become a common mechanism of injury. This study examines the relationship between when riders are using these devices (i.e. day of week, and time of the day) and injury incidence based on data from a large U.S. city. MethodsThis study is a retrospective cohort study of patients in the trauma registry at a level one trauma center. Registry data were combined with a publicly available dataset of all e-scooter trips that occurred during the study period. Frequency of injuries and trips were analyzed using ANOVA. Poisson regressions were conducted to calculate incidence rate ratios associated with injury incidence by day of the week and time of day. ResultsA total of 194 injured e-scooter patients were admitted to the trauma center during the study period. Patients were injured most often on Fridays (21%) and most often presented between 18:00–23:59 (38%). E-Scooter riders in general, most often rode on Saturdays (20%) and between 12:00–17:59 (44%). There was no significant relationship between day of week and injury. Riders in the early morning (IRR = 16.7, p < .001 95% CI: 10.5, 26.6), afternoon (IRR = 2.0, p = .01 95% CI: 1.2, 3.4), and evening (IRR = 3.7, p < .001 95% CI: 2.3, 6.2) had significant increased injury incidence compared to morning riders. ConclusionE-Scooter injury incidence varies by the time of day. The time of day in which a person rides an e-scooter can have a significant impact on the likelihood that the person will sustain an injury.