Mobility is a key factor in metropolitan life in Spain, where many citizens regularly move between municipalities for work, education, caregiving, leisure, and personal development. Effective metropolitan mobility planning is essential for sustainable urban development, social inclusion, and climate action. Despite its importance, political analyses of mobility—especially regarding inter-municipal cooperation—remain scarce. This project builds on the METROGOV initiative, which created the first database of metropolitan governance instruments across 45 Spanish urban areas and explored Spain’s institutional anomaly in the European context. Mobility emerged as the most developed and widespread policy area, with numerous governance tools already in place. METROMOV aims to deepen the institutional analysis of metropolitan mobility governance. It will examine which governance instruments are most common, why some urban areas are more advanced, and which models best support integrated and sustainable mobility policies. The research will unfold in three phases: (1) updating and expanding the database with a focus on mobility, (2) conducting qualitative case studies through document analysis and interviews, and (3) analyzing and disseminating findings. The goal is to inform the implementation of Spain’s Sustainable Mobility Law by aligning it with the country’s diverse metropolitan realities.