Mobility and access to basic supply, education and working facilities is essential for participation in social, economic, professional and cultural activities. As new transport solutions contribute to an increase in inter- and multimodal mobility, the provision of seamless mobility options has an influence on the accessibility of everyday services for individuals, especially in rural regions. Thus, ‘intermodal accessibility’ to regional centres (i.e. locations where everyday goods and services are provided) comprises both providing people with basic services in space and the quality of the local transport infrastructure. This study presents the development of a GIS-based tool that facilitates an area-wide analysis of the population’s intermodal accessibility to regional centres. Spatial indicators, which have a substantial influence on intermodal accessibility, are identified and weighted according to their impact. The set of indicators comprises factors reflecting the quality of the public transport service and station as well as comparative factors. Standardized data and interfaces such as GIP or VAO provide detailed spatial information on the multimodal transport infrastructure and support the transferability of the tool. Based on the resulting intermodal accessibility measure, regional disparities and areas with a poor transportation infrastructure can be identified. As the strategy developed here provides information on intermodal accessibility for the whole State of Salzburg in a transferable and transparent way, it contributes to integrative transport and settlement planning as well as to the assessment of specific locations.