This paper aims to evaluate the level of spatial accessibility of the new urban rail systems in the city of Thessaloniki, that is the metropolitan network under construction by Attiko Metro S.A. and the proposed tramway lines by Thessaloniki Public Transport Authority. Accessibility measures constitute a suitable planning tool for assessing the spatial impacts of transport scenarios, the transport networks connectivity and the land use transport interactions. In this research, location-based measures were applied, such as the integral, the isochronic and the potential accessibility indicators. The 2011 population census data in reference to the city block level and the origin-destination travel time data between the 68 future urban rail stations (simulated by GIS software) were used to calculate the relevant indicators. Thus, population accessibility was measured rather than opportunity accessibility, which is the usual research practice, due to the lack of adequate employment or land use data at the city block level. Nevertheless, the results can be interpreted as the potential attractiveness of the new urban rail stations. The analysis outlines the connectivity weaknesses of the proposed Metro and Tram system and therefore the direction for possible improvements on the urban rail network spatial coverage.