This paper addresses the urgent challenge of managing post-wildfire flood risk as climate-driven disasters intensify across Europe. Using the 2018 Kineta flood in Greece as a case study, it provides the first clear evidence that low-cost protective measures—costing only a small fraction of the actual damages—could have prevented millions in losses, demonstrating strong cost-effectiveness and tangible flood-mitigation benefits. The findings have important implications for public safety, urban planning, and disaster-risk policy, supporting a broader shift from reactive response to proactive, resilience-focused climate adaptation, particularly in fire-prone Mediterranean regions.