| ZIP | Locality | Prov | Region | Area Code | Belfiore | Notes | Locality | area code |
|---|---|---|---|---|---|---|---|---|
| 08025 | Oliena | NU | Sardinia | 0784 | G031 | Oliena NU - Sardinia | 0784 | |
| 08020 | Ollolai | NU | Sardinia | 0784 | G044 | Ollolai NU - Sardinia | 0784 | |
| 08020 | Olzai | NU | Sardinia | 0784 | G058 | Olzai NU - Sardinia | 0784 | |
| 08020 | Onanì | NU | Sardinia | 0784 | G064 | Onanì NU - Sardinia | 0784 | |
| 08020 | Onifai | NU | Sardinia | 0784 | G070 | Onifai NU - Sardinia | 0784 | |
| 08020 | Oniferi | NU | Sardinia | 0784 | G071 | Oniferi NU - Sardinia | 0784 | |
| 08026 | Orani | NU | Sardinia | 0784 | G084 | Orani NU - Sardinia | 0784 | |
| 08027 | Orgosolo | NU | Sardinia | 0784 | G097 | Orgosolo NU - Sardinia | 0784 | |
| 08028 | Orosei | NU | Sardinia | 0784 | G119 | Orosei NU - Sardinia | 0784 | |
| 08020 | Orotelli | NU | Sardinia | 0784 | G120 | Orotelli NU - Sardinia | 0784 |