Infrastructure is the point at which sustainability becomes irreversible: once built, assets lock in resilience or fragility for generations. As global demand for new trade infrastructure accelerates — driven by urbanization, climate impacts, and economic growth — both the risks of linear, carbon-intensive systems, and the advantages of circular, resilient design rise. Material use, construction choices, maintenance regimes, and natural-system integration determine long-term economic stability. With cities yet to build most of their 2050 infrastructure, the chapter stresses the urgency of circular approaches that reduce waste, cut embodied carbon, and extend asset lifespans. Case studies, from ports adapting to sea-level rise to innovations in green buildings, illustrate how circular infrastructure enhances competitiveness, lowers long-term costs, and mitigates physical and geopolitical risks. Circular infrastructure is essential to securing resilience, economic continuity, and national competitiveness in a resource-constrained world.