The twin transition, encompassing both digital and green transition, is a key challenge for Europe. In this study, we shift attention to the twin transition of technological knowledge bases of European regions. We employ an empirically grounded agent-based model (ABM) that allows to simulate technological knowledge creation – as captured by patents – of innovative agents in green and digital domains. Aggregated to the regional level, we use the model output to explore how local micro-level knowledge creation dynamics shape the regional twin transition progress. The twin transition trajectories are then further analysed through the lens of regional path development, meaning that the type of paths regions follow in the process of greening and digitalizing their knowledge bases are identified.