Autonomous vehicles have the potential to introduce numerous changes, opportunities, and innovations in mobility services, environment, data, value networks, and economy, among others. These automated vehicles are expected to impulse a disruptive change in society, especially within transport technology economics, travel behavior, and network performance. This introduces new challenges and opportunities for the automotive industry and society. Mobility as a Service could take a significant role in the utilization of autonomous vehicles, especially with the current downwards tendency of car ownership in Europe and North America. The scientific literature and consultancy firms reinforce this by providing analysis and predicting a decline of car ownership in the global markets. Nevertheless, there is a need for trust and more secure and tamper-resilient processes within autonomous vehicles and Mobility as a Service ecosystems. Because of this, the idea of this research is to explore what a Blockchain-based Mobility-as-a-Service concept design operated by Autonomous Vehicles would look like, elemental systems, requirements, and possible configurations. This research is conducted from a complex socio-technical point of view that considers a Design Science Research methodology. By doing so, a set of requirements are developed to create a Blockchain architecture, business processes and a reference architecture that will serve as a proof of concept of how a Blockchain-based Mobility-as-a-Service concept design operated by Autonomous Vehicles would look like. Later the artefacts and the process realized in this research are evaluated through a semi-structured interview process. By doing so, some corrections were included in the final design but in general positive impression were given by the experts. This research could be useful to have a first approach on the requirements, BC architecture, business processes and reference architecture of a Blockchain-based Mobility-as-a-Service concept design operated by Autonomous Vehicles. In this regard, Mobility as a Service operators could find this research helpful to start creating or implementing such a system.