The first mile/last mile (FM/LM) problem in public transport refers to the spatial accessibility of public transport and is the most important factor determining whether an individual will choose public transport. The FM/LM problem in Stockholm County, Sweden, was evaluated using a Geographic Information System estimating distances to public transport for the years 2019 and 2035. Overall, the population in Stockholm County, have good access to public transport. However, access varies with abilities, with elderly having 50 percent and elderly impaired 15 percent of their area within walking distance to public transport compared with the average citizen. Planned developments can provide good access to public transport, with extensive improvements for the elderly. However, inadequate planning for population increase will likely decrease the perceived public transport accessibility. Apartments and commercial buildings in the study area have high access to public transport. Elderly people have good access within city and regional centers, while access could be improved in other areas. Inclusion of FM/LM in the planning support system used in Stockholm could help mitigate FM/LM problems and extend access to public transport to all people of different abilities. This is vital in creating sustainable mobility networks and achieving sustainable development in smart cities.