Regarding the influence of the COVID-19 pandemic on mental health, there are concerns about the risk of lasting effects, especially among young people. In this study, we aimed to clarify the influence of the COVID-19 pandemic experience on the mental health of university students in the post-pandemic era and conducted a nationwide questionnaire survey and analyzed 331 responses. As a result, the experiences during the pandemic, such as general activity restrictions, self-growth or the importance of family and friends, infection prevention behaviors or restrictions of conversations with friends, reunion with family, new learning methods, or new hobbies and activities, were significantly associated with better mental health and resilience in the post-pandemic period. These results suggest that the COVID-19 pandemic experience may have a positive impact on the mental health of university students in the post-pandemic era.