The COVID-19 pandemic has generally destroyed the global tourism industry and threatened the recovery of destinations in developing countries facing more challenges from increasingly serious waves of the pandemic. Although many studies have attempted to measure the general impacts of COVID-19 pandemic, very few research has been conducted to assess its overall impact on a specific tourism destination throughout many waves of the pandemic. This research aims for exploring how a tourism economy in a developing country context was damaged after many waves of the COVID-19 damage. A typical emerging city in Vietnam experiencing three waves of COVID-19 pandemic has been selected as a case study. The study recruited 40 representatives of tourism-related organizations for the in-depth interviews while 280 questionnaires were distributed to the participants of different tourism organizations. The findings indicate that the majority of tourism business of the examined case study have seriously suffered from the pandemic whereas very few tourism-related enterprises were able to recover after the first wave of the pandemic. Unfortunately, the tourism business sectors were found to be on the brink of bankruptcy or facing permanent shutdown after the third wave. All the tourism enterprises generally appeared to experience a sharp drop of the number of customers, tourism revenue, service facilities and exploitation, and employee downsizing but the degree of the downturn differed among the examined enterprises. Among the tourism enterprises, travel agency and accommodation sector were found to suffer the most economic loss, compared to other stakeholders. In general, the COVID-19 pandemic’s impact on the tourism business in Vietnam is a big concern which may require timely economic policy response and financial scheme to better support local enterprises to cope with the challenges in post-pandemic recovery.