Abstract. The Project that is being described in this volume is a Thesis for the ―Geoinformatics‖ Postgraduate Studies Programme of the National Technical University of Athens. Goal of the Project was the implementation of an Intermodal Journey Planner for Athens‘ region, targeting its foreign visitors. Thus, the service was designed to be easy in use and capable to provide a good routing solution with only a few steps. Additionally, the language of the user interface is English. The service is provided by a web interface and is based mainly on open source software. Its development was the frame for the acquisition of knowledge regarding Java, Web Sites‘ Creation, Rich Internet Applications, Routing, Data Manipulation, as also regarding open source software development and team collaboration.