Municipalities
| Municipality | Population (2025) | km² | per km² |
|---|---|---|---|
| San Sebastián ★ | 189,866 | 59.7 | 3,180 |
| Irun | 63,835 | 42.9 | 1,488 |
| Errenteria | 39,363 | 32.6 | 1,207 |
| Eibar | 27,484 | 24.7 | 1,113 |
| Zarautz | 23,496 | 13.7 | 1,715 |
| Mondragón | 22,450 | 31.5 | 713 |
| Hernani | 20,375 | 40.8 | 499 |
| Tolosa | 20,070 | 38.2 | 525 |
| Lasarte-Oria | 19,435 | 7.1 | 2,737 |
| Hondarribia ★ | 16,788 | 30.6 | 549 |
| Pasaia | 15,820 | 12.2 | 1,297 |
| Azpeitia | 15,301 | 67.3 | 227 |
| Andoain | 14,517 | 28.6 | 508 |
| Bergara | 14,404 | 73.1 | 197 |
| Beasain | 14,048 | 30.3 | 464 |
| Azkoitia | 11,774 | 56.4 | 209 |
| Elgoibar | 11,705 | 39.9 | 293 |
| Oñati | 11,480 | 105.7 | 109 |
| Ordizia | 10,815 | 5.1 | 2,121 |
| Oiartzun | 10,480 | 56.7 | 185 |
| Zumaia | 10,160 | 10.5 | 968 |
| Zumarraga | 9,678 | 17.6 | 550 |
| Legazpi | 8,384 | 43.3 | 194 |
| Astigarraga | 7,812 | 11.8 | 662 |
| Aretxabaleta | 7,178 | 26.7 | 269 |
| Urretxu | 6,730 | 7.7 | 874 |
| Usurbil | 6,488 | 23.8 | 273 |
| Urnieta | 6,327 | 20.8 | 304 |
| Lezo | 6,184 | 8.8 | 703 |
| Orio | 6,184 | 9.5 | 651 |
| Lazkao | 6,087 | 11.1 | 548 |
| Villabona | 5,900 | 18.7 | 316 |
| Deba | 5,362 | 49.2 | 109 |
| Mutriku | 5,238 | 28.2 | 186 |
★ = municipality with a dedicated guide. Municipalities with at least 5,000 inhabitants are listed.