The “X-minute city” concept is based on the principle of urban planning at the human-scale. In terms of mobility, main activities should be accessed within a range of a few minutes by bicycle or on foot, decreasing the dependency on mechanised and, namely, automobile transport. This is expected to have positive impacts on the quality of life and of the natural and built environment. Several cities worldwide, such as Paris, Montréal and Melbourne, are developing initiatives towards this direction. On the other hand, most small and medium sized cities in Greece have not yet engaged into similar projects. These cities present the competitive advantages of short time-distances by active transport to main activities and of the relatively simple structure of their transport network allowing for game-changing strategic interventions, adjustable to their specific features and needs. In this context, the current research presents the case study of Volos, a medium sized Greek city, with a twofold purpose, i.e.: The assessment of time-distance from all building blocks to main activities by active transport in terms of the X-minute criterion; and the suggestion of city-specific transport policies towards the implementation of the “X-minute city” planning approach. The assessment of time-distance derives entirely from the processing of open geospatial data. The main results indicate that walking and, especially, cycling may currently provide access to main activities within a range of 15–20 min from residence, but specific policies are essential to increase the attractiveness and safety of these modes.