Mobility as a Service (MaaS) is considered a strategy that can provide potential solutions for a sustainable trans- port system. The current literature claims that MaaS can deliver net positive impacts for the transport system. However, whether these impacts are marginal or significant is unclear, as estimations typically are based on a few pilot tests. The lack of understanding of these impacts could create barriers for decision-making on policy and regulation in adopting MaaS strategy. The paper proposes a feasible evaluation to explore how and to what extent MaaS leads to, for example, reduced emissions, reduced fossil energy consumption, reduced car owner- ship and vehicle kilometres travelled on a large scale. The aim of this paper is to provide potential values of MaaS impacts based on analysis of future scenarios. The potential values of MaaS impacts can be used to support decision-making within both public organisations and among service developers for MaaS implementation and development.