| Locality | Post Code |
|---|---|
| Kakunishi (大分市) | 870-0850 |
| Kamihanda (大分市) | 870-1111 |
| Kamihetsugi (大分市) | 879-7764 |
| Kamikasugamachi (大分市) | 870-0817 |
| Kamimunakata (大分市) | 870-1152 |
| Kamishiraki (大分市) | 870-0805 |
| Kamitsume (大分市) | 870-1215 |
| Kamiyahata (大分市) | 870-0808 |
| Kanaikemachi (大分市) | 870-0026 |
| Kanaikeminami (大分市) | 870-0839 |
| Kanamemachi (大分市) | 870-0831 |
| Kanayazako (大分市) | 870-0879 |
| Kano (大分市) | 870-0926 |
| Kasugaura (大分市) | 870-0011 |
| Katashima (大分市) | 870-0943 |
| Katashimadai (大分市) | 870-0949 |
| Katsuragi (大分市) | 870-0133 |
| Kawarauchi (大分市) | 879-7503 |
| Kei (大分市) | 870-0124 |
| Kentokumachi (大分市) | 870-0025 |
| Keyakidai (大分市) | 879-7762 |
| Kibogaoka (大分市) | 870-0959 |
| Kichobaru (大分市) | 870-0809 |
| Kida (大分市) | 870-0311 |
| Kinoe (大分市) | 870-1161 |
| Kinosaka (大分市) | 870-0870 |