Travelling and moving within urban areas in a sustainable way acquires a transition toward sustainable commuting modes. An approach to reaching the transition is recognised as sustainable mobility. According to smart mobility research, autonomous shuttle buses could contribute to achieve sustainable mobility in urban areas. This study therefore aims to evaluate to what extent autonomous shuttle buses are contributing to achieve sustainable mobility in Lindholmen and Barkarbystaden, by analysing the enabling and challenging factors of integrating autonomous shuttle buses from a spatial planning perspective. Based on a thematic analysis, three themes: integration into transport networks, urban policy integration, and spatial planning and urban design integration, emerged from a multiple-case study and an in-depth interview study. It is revealed that the buses are bringing forth a multi-modal transportation network with an extension of sustainable travel opportunities beyond the privately owned car. Nonetheless, it is evident that the autonomous shuttle buses are not eligible to cover the first-last mile accessibility gap in Lindholmen nor Barkarbystaden. Practitioners should therefore consider evaluating what autonomous shuttle buses should be used for, how and where before they decide to go any further with the integration of autonomous shuttle buses in other urban areas.