The present paper deals with intermodal integration as a measure to embrace new transit modes into current public transport systems. The contents are divided into a theoretical re-view and the development of the case study in Thessaloniki, Greece. The former includes a definition of integration and the determination of its several levels: operational (composed of layout, schedule, and information, fare and ticket integration), physical, and organizational. Throughout the second part, the case study of Thessaloniki is developed, where the construction of a new metro system will transform the current bus-only system into a bimodal transit network. The future operation of the two modes and their multiple lines by different agencies calls for an integration strategy to ensure coordination and cooperation of all involved parties. As the metro system is currently under construction, the first step is ensuring layout integration. Therefore, the current transit offer is analyzed, and deficiencies regarding layout integration are identified. Finally, the detailed design of a new bus system is proposed in order to establish a new network plan with clear roles and structured hierarchy. The new layout consists of a three-leveled network with specific functions and performance characteristics for each level, ensuring good connectivity and coordination between the modes and lines.