The non-pharmaceutical interventions implemented to prevent the spread of COVID-19 have affected the epidemiology of other respiratory viruses. In South Korea, Human metapneumovirus (HMPV) typically occurs from winter to the following spring; however, it was not detected for two years during the COVID-19 pandemic and re-emerged in the fall of 2022, which is a non-epidemic season. To examine the molecular genetic characteristics of HMPV before and after the COVID-19 pandemic, we analyzed 427 HMPV-positive samples collected in the Gwangju area from 2018 to 2022. Among these, 24 samples were subjected to whole-genome sequencing. The results showed a shift in the predominant genotype from A2b2 before the COVID-19 pandemic to A2b1 in 2022. Furthermore, a significant increase in HMPV cases was observed in the 6–10-year age group. Since the onset of the COVID-19 pandemic, social distancing have reduced the possibility of HMPV exposure and herd immunity due to non-transmission, resulting in the introduction of new HMPV genotypes in different seasons.