This report examines the potential impact of Mobility as a Service (MaaS) on how passenger transport is currently organised. MaaS is a model for supplying a wide range of passenger transport services through a single, digital customer interface. In its most ambitious form, it integrates different transport, information and payment services into a smooth and reliable customer experience. The report assesses the regulatory and governance requirements for integrating MaaS with public transport and ensuring it delivers more sustainable urban mobility, focusing on the role of public transport authorities.