This paper relates the experience of geologists piloting the use of 3D geological models on tunnelling projects in Europe. 3D models were proven to be an aid to the geologist’s own interpretations, but also found to be invaluable for communication to tunnel designers and non-technical clients. The Karavanke tunnel alignment traverses’ complex geological structures with a high degree of fracturing and folding, with up to a kilometre of overburden. Historical investigations, surface maps and face maps from a neighbouring tunnel tube already constructed were digitised in 3D space as a basis of a conceptual model covering the Slovenian half of the project. The model was used as the basis for conceptual design of the support structures and enabled the design to be evaluated in the context of the geology. The model was also used to both justify, position and interpret further ground investigations for the design phase. The success of the 3D model as a communication tool and visual database of ground investigations has led to the extension of the model to encompass the Austrian section of the alignment. In this process there have been challenges to overcome to unify the model. Additionally, a separate pilot project was used to validate integration of digital face mapping into 3D models during construction. The upcoming construction phase will utilise cross discipline Building Information Modelling (BIM) practises and further leverage the 3D model in this process.