Postal codes in Kosai-shi, Shizuoka
静岡県湖西市 — 29 postal codes. General code: 431-0400. Local government code 22221.
Address example
1-2-3 Araicho Arai, Kosai-shi, Shizuoka 431-0302, Japan
〒431-0302 静岡県湖西市新居町新居1-2-3
Replace 1-2-3 with the chome-ban-go (block and lot) number, and add the building and room number before it.
| Postal code | Town / English address |
|---|---|
| 431-0400 | (any other address in this municipality) （下に掲載がない場合） Kosai-shi, Shizuoka 431-0400, Japan |
| 431-0302 | Araicho Arai 新居町新居 Araicho Arai, Kosai-shi, Shizuoka 431-0302, Japan |
| 431-0304 | Araicho Uchiyama 新居町内山 Araicho Uchiyama, Kosai-shi, Shizuoka 431-0304, Japan |
| 431-0301 | Araicho Nakanogo 新居町中之郷 Araicho Nakanogo, Kosai-shi, Shizuoka 431-0301, Japan |
| 431-0303 | Araicho Hamana 新居町浜名 Araicho Hamana, Kosai-shi, Shizuoka 431-0303, Japan |
| 431-0411 | Iride 入出 Iride, Kosai-shi, Shizuoka 431-0411, Japan |
| 431-0412 | Uchiura 内浦 Uchiura, Kosai-shi, Shizuoka 431-0412, Japan |
| 431-0425 | Umeda 梅田 Umeda, Kosai-shi, Shizuoka 431-0425, Japan |
| 431-0427 | Ekiminami 駅南 Ekiminami, Kosai-shi, Shizuoka 431-0427, Japan |
| 431-0404 | Ota 太田 Ota, Kosai-shi, Shizuoka 431-0404, Japan |
| 431-0403 | Ochiba 大知波 Ochiba, Kosai-shi, Shizuoka 431-0403, Japan |
| 431-0422 | Okasaki 岡崎 Okasaki, Kosai-shi, Shizuoka 431-0422, Japan |
| 431-0432 | Kazenomori 風の杜 Kazenomori, Kosai-shi, Shizuoka 431-0432, Japan |
| 431-0405 | Kanza 神座 Kanza, Kosai-shi, Shizuoka 431-0405, Japan |
| 431-0441 | Kibi 吉美 Kibi, Kosai-shi, Shizuoka 431-0441, Japan |
| 431-0442 | Komi 古見 Komi, Kosai-shi, Shizuoka 431-0442, Japan |
| 431-0452 | Sakaijuku 境宿 Sakaijuku, Kosai-shi, Shizuoka 431-0452, Japan |
| 431-0451 | Shirasuka 白須賀 Shirasuka, Kosai-shi, Shizuoka 431-0451, Japan |
| 431-0421 | Shinjo 新所 Shinjo, Kosai-shi, Shizuoka 431-0421, Japan |
| 431-0423 | Shinjo Okasaki Umedanyukaichi 新所・岡崎・梅田入会地 Shinjo Okasaki Umedanyukaichi, Kosai-shi, Shizuoka 431-0423, Japan |
| 431-0424 | Shinjohara 新所原 Shinjohara, Kosai-shi, Shizuoka 431-0424, Japan |
| 431-0426 | Shinjohara Higashi 新所原東 Shinjohara Higashi, Kosai-shi, Shizuoka 431-0426, Japan |
| 431-0428 | Tokiwa ときわ Tokiwa, Kosai-shi, Shizuoka 431-0428, Japan |
| 431-0444 | Boze 坊瀬 Boze, Kosai-shi, Shizuoka 431-0444, Japan |
| 431-0429 | Minamidai 南台 Minamidai, Kosai-shi, Shizuoka 431-0429, Japan |
| 431-0443 | Yamaguchi 山口 Yamaguchi, Kosai-shi, Shizuoka 431-0443, Japan |
| 431-0401 | Yokoyama 横山 Yokoyama, Kosai-shi, Shizuoka 431-0401, Japan |
| 431-0402 | Riki 利木 Riki, Kosai-shi, Shizuoka 431-0402, Japan |
| 431-0431 | Washizu 鷲津 Washizu, Kosai-shi, Shizuoka 431-0431, Japan |
Source: Japan Post postal code data (UTF-8 edition, updated Aug 31, 2026) and romanized edition (KEN_ALL_ROME, June 2025). Japan Post does not claim copyright on postal code data and allows free redistribution. Romaji follows Japan Post (long vowels are not marked). * = romanized by this site from the kana reading because the town is not yet in the romanized edition.