Book excerpt: ASEAN Economic Community (AEC) building is a long journey. For continued relevance and impact, the AEC must remain dynamic while taking into consideration evolving contexts and emerging opportunities and challenges. Notable progress has been made under the two AEC Blueprints (2015 and 2025), particularly in laying down the frameworks for regional economic integration and community building. Nonetheless, gaps remain in implementation, calling for a more streamlined but result-oriented agenda and stronger institutional coordination. Today, the AEC is faced with a markedly different context and unprecedented challenges resulting from a poly-crisis, involving geo-economic fragmentation, supply chain restructuring, and climactic changes. Without adjustment, ASEAN’s pillar and sector-centric approach can be expected to fall short in effectively responding to these challenges. As AEC 2025 enters its final quarter, ASEAN needs to recalibrate its priorities. It also increasingly needs to take a whole-of-community approach to integration, as issues and their solutions are spread across multiple sectors. Furthermore, as it develops the AEC Post-2025 agenda, it needs to strike a balance between ambition and pragmatism, and to support substance with institutions and processes.