SAN MATEO — CA
Data last updated: March 10, 2026
Area Codes
Top Carriers
| Carrier | OCN | NXX Count |
|---|---|---|
| PACIFIC BELL | 9740 | 49 |
| NEW CINGULAR WIRELESS PCS, LLC | 6010 | 18 |
| T-MOBILE USA, INC. | 6529 | 15 |
| CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | 6006 | 7 |
| ONVOY, LLC - CA | 649C | 5 |