ObjectiveMany factors influence patient flow through an ED, including streaming, treatment spaces and staff resources. This pilot study explored and compared real time patient flow using a single‐stream system versus varying configurations of possible two‐stream systems using computer simulation.MethodsSimulation modelling was used to assess the delay in treatment of a rapid‐antigen‐tested‐based, two‐stream model for patient flow through ED during the peak phase of the COVID pandemic.ResultsModelling two‐stream configuration for all patients (minimum time to be seen for both COVID‐positive and COVID‐negative patients) showed that in the case study ED, a two‐stream system and linked changes in bed configuration for managing the risks of infection can impact delays in treatment.ConclusionsData‐driven modelling within specific clinical settings can inform the (in)efficiency of patient flow processes and help clinicians and managers make evidence‐based decisions about patient transition through EDs. This can assist with reconfiguration of ED patient streaming particularly during periods of unique need, such as the recent COVID‐19 pandemic.