| City | 2026 Pop. ↓ |
|---|---|
| Ichikawa | 529,324 |
| Ichinomiya | 513,045 |
| Iwaki | 449,410 |
| Ichihara | 363,819 |
| Ibaraki | 311,781 |
| Isesaki | 285,968 |
| Izumo | 233,222 |
| Izumi | 228,735 |
| Iwata | 224,984 |
| Imabari | 204,736 |
| Itami | 199,659 |
| Ishinomaki | 189,184 |
| Inazawa | 181,895 |
| Isahaya | 180,681 |
| Iruma | 176,420 |
| Iwakuni | 174,301 |
| Iizuka | 170,574 |
| Ise | 165,715 |
| Ichinoseki | 151,092 |
| Ikoma | 147,314 |
| Inzai | 138,508 |
| Isehara | 137,389 |
| Izumisano | 126,889 |
| Ikeda | 120,898 |