ABSTRACT This article investigates long-term adaptation and resilience to floods at World Heritage sites through a case study of Hoi An Ancient Town, Quang Nam, Vietnam. Drawing on fieldwork observation, document review, and unstructured interviews conducted in Hoi An, we examine the enduring processes and experiences of co-living with floods. The article considers residents’ ability to comprehend, acknowledge, and address the challenges of flooding using the conceptual lens of adaptation and adversity acceptance as resilience. Our findings reveal an inseparable bond between residents and their built environment, encompassing invaluable lessons and experiences, local beliefs, resource availability, and adaptive strategies aimed at harmonious cohabitation with flooding described as ‘leaning into nature’. Strikingly, residents have developed their own practices and identities shaped by the town’s inundation by flood waters over a few centuries. Various modern flood prevention measures trace their origins to historical efforts, underscoring the vital role of traditional knowledge and practices in coping with the impacts of climate change. Those efforts are also framed within the local policy context such as Heritage Management Plan, Disaster Risk Management Plan, and Regulation for the Protection of the UNESCO-listed Hoi An Ancient Town.