Mobility as a service (MaaS) promises the seamless and customized integration of the mobility services in a certain region into one digital platform, via which users can plan, book, and pay their trips. Although prior research indicates that MaaS can decrease greenhouse gas emissions and improve inclusiveness of the transport system, the user numbers remain low. The deployment of incentives can influence the mobility decisions of travelers and might encourage the adoption of MaaS platforms, if the incentives match the preferences of the potential users. Against this background, we present the results of a stated-preference choice experiment, in which participants choose between MaaS platforms that vary regarding the included incentives. We weigh different economic, social, and ecological incentives against each other and generate insights about their attractiveness for potential users. The choice experiment shows a high importance of both ecological and economic incentives, while revealing a relatively lower importance of social attributes. Our study contributes to the understanding of incentives for MaaS usage and gives impulses for the research on MaaS platform and bundle optimization. The results further serve as insights for policy-makers and practitioners with the aim of increasing the user numbers of MaaS systems and improving the sustainability of the transportation sector.