Phone numbers in Millbrae, California
Millbrae has 24 phone prefixes in area code 650.
Biggest holders: AT&T (local phone), MCImetro (Verizon Business), AT&T Mobility. This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 29%
- Local phone company 25%
- Internet / business phone carrier 46%
Every prefix in Millbrae
Search the first six digits of a number in this list. If it's here, the number started in Millbrae with the carrier shown. If it isn't, check the California page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 650-204 | Level 3 (Lumen) | Internet / business phone carrier | – |
| 650-231 | MCImetro (Verizon Business) | Internet / business phone carrier | – |
| 650-239 | Onvoy | Internet / business phone carrier | – |
| 650-259 | AT&T (local phone) | Local phone company | – |
| 650-302 | AT&T Mobility | Mobile carrier | – |
| 650-307 | T-Mobile (including Sprint) | Mobile carrier | 2001 |
| 650-409 | Tpx Communications | Internet / business phone carrier | – |
| 650-443 | Tpx Communications | Internet / business phone carrier | – |
| 650-455 | AT&T Mobility | Mobile carrier | – |
| 650-490 | AT&T Mobility | Mobile carrier | 2002 |
| 650-552 | AT&T (local phone) | Local phone company | – |
| 650-609 | T-Mobile (including Sprint) | Mobile carrier | 2021 |
| 650-648 | MCImetro (Verizon Business) | Internet / business phone carrier | – |
| 650-651 | MCImetro (Verizon Business) | Internet / business phone carrier | – |
| 650-652 | AT&T (local phone) | Local phone company | – |
| 650-672 | Onvoy | Internet / business phone carrier | 2022 |
| 650-684 | Level 3 (Lumen) | Internet / business phone carrier | – |
| 650-686 | MCImetro (Verizon Business) | Internet / business phone carrier | – |
| 650-689 | Teleport Communications America | Internet / business phone carrier | – |
| 650-692 | AT&T (local phone) | Local phone company | – |
| 650-697 | AT&T (local phone) | Local phone company | – |
| 650-732 | Verizon Wireless | Mobile carrier | – |
| 650-777 | AT&T (local phone) | Local phone company | – |
| 650-942 | Verizon Wireless | Mobile carrier | 2003 |
Most prefixes are pooled: the 10,000 numbers in each are handed out in blocks of 1,000 to different carriers, and people can also take their numbers to another carrier. So the carrier shown is where the prefix started, not a guarantee about any one number. Source: NANPA central office code records, 2026-10-10.