The COVID-19 pandemic has profoundly affected internal migration patterns worldwide. Most previous studies have reported on pandemic-induced changes in internal migration using data from 2020 and 2021. Therefore, little is known about the pandemic’s medium-term impact. To address this gap, this study investigated an annual series of migration patterns from 2019 to 2023 in Japan. At the municipal level, relationships between net migration rates and population density indicated that the urbanisation trend became weak in 2020, compared to that in 2019, and it was the weakest in 2021. The urbanisation degree became stronger in 2023, increasing to the level in 2020. Using annual inter-municipal migration flows, this study then investigated changes in migration flows to/from and within three major metropolitan areas (Tokyo, Nagoya, and Osaka). The changes in sizes of these flows and migration effectiveness index suggested that the pandemic had the largest impact in the Tokyo metropolitan area, among the three areas, and it stimulated intra-metropolitan migration as suburbanisation, rather than net out-migration as ‘urban exodus’, in Japan. The overall results indicated that the pandemic had the largest impact in 2021, which got smaller as the migration patterns recovered to the pre-pandemic ones in 2023.