Los prefijos de Mongolia (códigos de área):
| Ciudad/pueblo o región | Prefijo | |
|---|---|---|
| 1. | Sagil | 4553 |
| 2. | Sagsai | 4249 |
| 3. | Saikhan (Khötöl) | 3651 |
| 4. | Saikhan (Saikhan-Ovoo) | 3451 |
| 5. | Saikhan-Ovoo | 5952 |
| 6. | Saikhandulaan | 5249 |
| 7. | Sainshand city | 522 |
| 8. | Sant | 3253 |
| 9. | Sant | 3652 |
| 10. | Santmargats | 4653 |
| 11. | Selenge (Khyalganat) | 3452 |
| 12. | Sergelen | 5848 |
| 13. | Sergelen | 2764 |
| 14. | Sevrei | 5349 |
| 15. | Shaamar (Dulankhaan) | 3657 |
| 16. | Sharga | 4857 |
| 17. | Sharyngol | 3743 |
| 18. | Shilüüstei | 4653 |
| 19. | Shine-Ider | 3864 |
| 20. | Shinejinst | 4459 |
| 21. | Shiveegovi | 5442 |
| 22. | Songino | 4654 |
| 23. | Sükhbaatar | 5147 |
| 24. | Sükhbaatar city | 362 |
| 25. | Sümber | 2763 |