| Locality | Post Code |
|---|---|
| Kamitanakamachi (下関市) | 750-0009 |
| Kamono (下関市) | 759-6602 |
| Kanda (下関市) | 752-0907 |
| Kandacho (下関市) | 750-0044 |
| Kannonzakicho (下関市) | 750-0012 |
| Kanseicho (下関市) | 750-0032 |
| Kanseihommachi (下関市) | 750-0022 |
| Karatocho (下関市) | 750-0005 |
| Kasugacho (下関市) | 750-0031 |
| Katachiyama (下関市) | 751-0884 |
| Katachiyamacho (下関市) | 751-0888 |
| Katachiyamamidorimachi (下関市) | 751-0885 |
| Kawanakahommachi (下関市) | 751-0859 |
| Kawanakayutakamachi (下関市) | 751-0853 |
| Kazumitsu (下関市) | 752-0904 |
| Kazumitsucho (下関市) | 752-0903 |
| Kibunemachi (下関市) | 751-0823 |
| Kikugawacho Higashinakayama (下関市) | 750-0302 |
| Kikugawacho Kamihoki (下関市) | 750-0307 |
| Kikugawacho Kamiokaeda (下関市) | 750-0321 |
| Kikugawacho Kamiono (下関市) | 750-0311 |
| Kikugawacho Kamitabe (下関市) | 750-0314 |
| Kikugawacho Kiba (下関市) | 750-0325 |
| Kikugawacho Kuno (下関市) | 750-0324 |
| Kikugawacho Kutsuwai (下関市) | 750-0305 |
| Kikugawacho Michiichi (下関市) | 750-0304 |