Due to public opposition against the unsustainability of hosting the Olympic Games, the International Olympic Committee adopted Olympic Agenda 2020 to adjust the event requirements to address modern society’s sustainability concerns. Since its implementation, the Agenda has driven important changes regarding the planning and organization of the Olympics, including the possibility of regions being hosts. This allows the sprawl of Olympic venues over larger territories, theoretically facilitating the alignment of event requirements with the needs of the intensively growing contemporary urban areas. However, the larger the host territory, the more complex becomes its mobility planning, as transport requirements for participants still have to be fulfilled, and the host populations still expect to inherit benefits from any investments made. The objective of this paper is to identify and discuss new challenges that such modifications bring for mega-event mobility planning. First, based on the academic literature of case studies of previous Olympic cities, a theoretical framework to systematize the mobility problem at the Olympic Games is proposed for further validation, identifying the dimensions of the related knowledge frames. Second, the mobility planning for the case study of the first ever Olympic region—the Milan–Cortina 2026 Winter Games—is described. Using this case study, the proposed framework is then extrapolated for cases of Olympic regions in order to identify any shifts in the paradigm of mobility planning when increasing the spatial scale of Olympic hosts. Conclusions indicate that, if properly addressed, unsustainability might be mitigated in Olympic regions, but mega-event planners will have to consider new issues affecting host communities and event stakeholders.