| Business | Phone |
| Us Post Office 135 W 25th Ave, San Mateo 94403 | (650) 000-1111 |
| Us Post Office 1630 S Delaware St, San Mateo 94402 | (650) 358-8490 |
| Us Post Office 210 S Ellsworth Ave, San Mateo 94401 | (650) 000-1111 |
| Us Post Office 2700 Campus Dr, San Mateo 94497 | (650) 377-1455 |