This study explores the spatial extent of daily mobility by analysing the activity spaces of suburban commuters. It deepens knowledge of the transport‐related consequences of functionally segregated areas within metropolitan regions, detecting the most significant factors (personal and environmental) affecting the size of activity spaces of people with a suburban commute. Additionally, a comparison between new and traditional calculation methods of activity spaces has been carried out. To enable this, an app was developed for smartphones enabled with a global positioning system (GPS) in order to obtain accurate tracking data for 233 members of the Autonomous University of Barcelona in the Metropolitan Region of Barcelona, Spain. Results show that spatio‐temporal factors together with socioeconomic factors, such as the professional role, are strong determinants of the size of activity spaces. Moreover, differences between public and private transport modes of commuting were minimal, proving the potential of public transport as a non‐restricting means of transport even in suburban environments. Finally, the comparative analysis between calculation methods highlight that new methods produce more realistic representations of the spatial extent of everyday life, and different sets of explanatory factors emerge for activity spaces measured in different ways.