| Source | UN (World Urbanization Prospects 2025) |
| Date | 09 Feb 2026 |
| Code | City | Population | Share (%) | Rank | Change | |||
|---|---|---|---|---|---|---|---|---|
| 2025 | 2026 | Thailand | World | Population | (%) | |||
| Krun | Krung Thep Maha Nakhon (Bangkok) | 18,180,280 | 18,338,825 | 25.6 | 1 | 14 | 158,545 | 0.87 |
| Chia | Chiang Mai | 626,629 | 625,359 | 0.873 | 2 | 867 | -1,270 | -0.20 |
| Hat | Hat Yai | 407,059 | 406,270 | 0.567 | 3 | 1413 | -789 | -0.19 |
| Phuk | Phuket | 389,376 | 388,642 | 0.543 | 4 | 1477 | -734 | -0.19 |
| Lop | Lop Buri | 378,160 | 384,125 | 0.536 | 5 | 1499 | 5,965 | 1.58 |
| Chon | Chon Buri | 297,276 | 300,774 | 0.420 | 6 | 1941 | 3,498 | 1.18 |
| Khon | Khon Kaen | 274,613 | 272,502 | 0.380 | 7 | 2163 | -2,111 | -0.77 |
| Patt | Pattaya | 238,411 | 241,653 | 0.337 | 8 | 2459 | 3,242 | 1.36 |
| Nakh | Nakhon Pathom | 232,416 | 235,390 | 0.329 | 9 | 2522 | 2,974 | 1.28 |
| Nakh | Nakhon Ratchasima | 219,863 | 217,847 | 0.304 | 10 | 2753 | -2,016 | -0.92 |
| Phra | Phra Nakhon Si Ayutthaya | 211,344 | 213,899 | 0.299 | 11 | 2803 | 2,555 | 1.21 |
| Song | Songkhla | 213,186 | 212,793 | 0.297 | 12 | 2820 | -393 | -0.18 |
| Ubon | Ubon Ratchathani | 191,866 | 190,802 | 0.266 | 13 | 3189 | -1,064 | -0.55 |
| Phit | Phitsanulok | 189,643 | 188,532 | 0.263 | 14 | 3235 | -1,111 | -0.59 |
| Lamp | Lampang | 175,646 | 175,303 | 0.245 | 15 | 3495 | -343 | -0.20 |
| Nakh | Nakhon Si Thammarat | 151,713 | 151,392 | 0.211 | 16 | 4065 | -321 | -0.21 |
| Than | Thanyaburi | 146,811 | 148,552 | 0.207 | 17 | 4138 | 1,741 | 1.19 |
| Tha | Tha Chang | 133,416 | 139,098 | 0.194 | 18 | 4430 | 5,682 | 4.26 |
| Udon | Udon Thani | 139,189 | 137,896 | 0.193 | 19 | 4467 | -1,293 | -0.93 |
| Rano | Ranong | 126,669 | 126,433 | 0.177 | 20 | 4892 | -236 | -0.19 |
| Sura | Surat Thani | 126,423 | 126,151 | 0.176 | 21 | 4905 | -272 | -0.22 |
| Yala | Yala | 113,021 | 112,784 | 0.157 | 22 | 5541 | -237 | -0.21 |
| Chia | Chiang Rai | 112,713 | 112,197 | 0.157 | 23 | 5567 | -516 | -0.46 |
| Nakh | Nakhon Sawan | 105,331 | 104,854 | 0.146 | 24 | 5966 | -477 | -0.45 |
| Satt | Sattahip | 102,065 | 103,188 | 0.144 | 25 | 6073 | 1,123 | 1.10 |
| Sara | Saraburi | 99,411 | 100,730 | 0.141 | 26 | 6210 | 1,319 | 1.33 |
| Ban | Ban Phaeo | 97,791 | 100,474 | 0.140 | 27 | 6227 | 2,683 | 2.74 |
| Thal | Thalang | 100,444 | 100,260 | 0.140 | 28 | 6248 | -184 | -0.18 |