| Locality | Post Code |
|---|---|
| Yanushevka, Kostanay (Янушевка) | P47, P47 |
| Zarechnoe, Kostanay (Заречное) | P46, P47 |
| Zatobolsk, Kostanay (Затобольск) | P46, P47 |
| Zhambyl, Kostanay (Жамбыл) | P46, P47, P52 |
| Zhdanovka, Kostanay (Ждановка) | P46, P47 |
| Zhukovka, Kostanay (Жуковка) | P46, P47 |