| Source | UN (World Urbanization Prospects 2025) |
| Date | 10 Apr 2026 |
| Code | City | Population | Share (%) | Rank | Change | |||
|---|---|---|---|---|---|---|---|---|
| 2025 | 2026 | South Korea | World | Population | (%) | |||
| Seou | Seoul | 22,490,482 | 22,517,764 | 43.6 | 1 | 10 | 27,282 | 0.12 |
| Busa | Busan | 3,263,221 | 3,248,254 | 6.29 | 2 | 151 | -14,967 | -0.46 |
| Daeg | Daegu | 2,334,446 | 2,323,365 | 4.50 | 3 | 214 | -11,081 | -0.47 |
| Daej | Daejeon | 1,517,299 | 1,513,768 | 2.93 | 4 | 338 | -3,531 | -0.23 |
| Gwan | Gwangju | 1,441,495 | 1,438,457 | 2.78 | 5 | 355 | -3,038 | -0.21 |
| Ulsa | Ulsan | 881,858 | 877,731 | 1.70 | 6 | 601 | -4,127 | -0.47 |
| Cheo | Cheongju-si | 690,333 | 686,911 | 1.33 | 7 | 792 | -3,422 | -0.50 |
| Chan | Changwon | 665,772 | 662,616 | 1.28 | 8 | 823 | -3,156 | -0.47 |
| Jeon | Jeonju | 637,082 | 635,365 | 1.23 | 9 | 857 | -1,717 | -0.27 |
| Cheo | Cheonan-si | 428,378 | 427,478 | 0.827 | 10 | 1322 | -900 | -0.21 |
| Poha | Pohang-si | 382,368 | 380,518 | 0.736 | 11 | 1515 | -1,850 | -0.48 |
| Gumi | Gumi-si | 296,323 | 294,849 | 0.571 | 12 | 1992 | -1,474 | -0.50 |
| Gimh | Gimhae | 261,543 | 260,150 | 0.504 | 13 | 2272 | -1,393 | -0.53 |
| Mokp | Mokpo-si | 238,374 | 237,836 | 0.460 | 14 | 2491 | -538 | -0.23 |
| Chun | Chuncheon | 236,384 | 237,332 | 0.459 | 15 | 2502 | 948 | 0.40 |
| Jinj | Jinju-si | 237,707 | 236,273 | 0.457 | 16 | 2512 | -1,434 | -0.60 |
| Wonj | Wonju | 230,065 | 231,200 | 0.447 | 17 | 2569 | 1,135 | 0.49 |
| Gimp | Gimpo | 178,424 | 178,701 | 0.346 | 18 | 3422 | 277 | 0.16 |
| Guns | Gunsan-si | 171,268 | 170,866 | 0.331 | 19 | 3594 | -402 | -0.23 |
| Iksa | Iksan-si | 164,566 | 164,174 | 0.318 | 20 | 3724 | -392 | -0.24 |
| Dong | Dongducheon | 153,631 | 155,338 | 0.301 | 21 | 3955 | 1,707 | 1.11 |
| Yang | Yangsan | 150,276 | 149,503 | 0.289 | 22 | 4103 | -773 | -0.51 |
| Sunc | Suncheon-si | 147,975 | 147,630 | 0.286 | 23 | 4172 | -345 | -0.23 |
| Pyeo | Pyeongtaek | 145,127 | 144,782 | 0.280 | 24 | 4267 | -345 | -0.24 |
| Hwad | Hwado | 131,457 | 131,609 | 0.255 | 25 | 4698 | 152 | 0.12 |
| Gang | Gangneung | 128,525 | 128,709 | 0.249 | 26 | 4815 | 184 | 0.14 |
| Chun | Chungju-si | 103,243 | 103,759 | 0.201 | 27 | 6038 | 516 | 0.50 |