| Locality | Postal Code |
|---|---|
| Oami (館山市) | 294-0044 |
| Oi (館山市) | 294-0002 |
| Oka (館山市) | 294-0031 |
| Okada (館山市) | 294-0024 |
| Others (館山市) | 294-0000 |
| Oto (館山市) | 294-0025 |
| Ryuoka (館山市) | 294-0232 |
| Sakadaru (館山市) | 294-0313 |
| Sakai (館山市) | 294-0311 |
| Sakuna (館山市) | 294-0029 |
| Sano (館山市) | 294-0225 |
| Shimosanagura (館山市) | 294-0048 |
| Shinjuku (館山市) | 294-0046 |
| Shiomi (館山市) | 294-0302 |
| Sono (館山市) | 294-0006 |
| Sunomiya (館山市) | 294-0223 |
| Sunosaki (館山市) | 294-0316 |
| Takai (館山市) | 294-0041 |
| Takewara (館山市) | 294-0001 |
| Tateyama (館山市) | 294-0036 |
| Uenohara (館山市) | 294-0042 |
| Yamamoto (館山市) | 294-0014 |
| Yamogi (館山市) | 294-0021 |
| Yawata (館山市) | 294-0047 |