Phone numbers in Los Altos, California
Los Altos has 28 phone prefixes in area code 650.
Biggest holders: AT&T (local phone), Onvoy, MCImetro (Verizon Business). This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 21%
- Local phone company 21%
- Internet / business phone carrier 57%
Every prefix in Los Altos
Search the first six digits of a number in this list. If it's here, the number started in Los Altos with the carrier shown. If it isn't, check the California page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 650-209 | Tpx Communications | Internet / business phone carrier | – |
| 650-229 | MCImetro (Verizon Business) | Internet / business phone carrier | – |
| 650-305 | T-Mobile (including Sprint) | Mobile carrier | 2002 |
| 650-383 | Teleport Communications America | Internet / business phone carrier | – |
| 650-397 | Bandwidth | Internet / business phone carrier | – |
| 650-405 | AT&T Mobility | Mobile carrier | 2018 |
| 650-469 | MCImetro (Verizon Business) | Internet / business phone carrier | – |
| 650-471 | Tpx Communications | Internet / business phone carrier | – |
| 650-472 | Level 3 (Lumen) | Internet / business phone carrier | – |
| 650-492 | AT&T Mobility | Mobile carrier | 2002 |
| 650-518 | MetroPCS (T-Mobile) | Mobile carrier | 2001 |
| 650-559 | AT&T (local phone) | Local phone company | – |
| 650-668 | Fractel | Internet / business phone carrier | 2020 |
| 650-680 | T-Mobile (including Sprint) | Mobile carrier | 2016 |
| 650-768 | Windstream (PAETEC) | Internet / business phone carrier | 2025 |
| 650-770 | Onvoy | Internet / business phone carrier | 2016 |
| 650-774 | Onvoy | Internet / business phone carrier | 2023 |
| 650-782 | TON80 Communications | Internet / business phone carrier | 2022 |
| 650-823 | AT&T Mobility | Mobile carrier | – |
| 650-887 | Onvoy | Internet / business phone carrier | – |
| 650-900 | Onvoy | Internet / business phone carrier | – |
| 650-917 | AT&T (local phone) | Local phone company | – |
| 650-935 | MCImetro (Verizon Business) | Internet / business phone carrier | – |
| 650-941 | AT&T (local phone) | Local phone company | – |
| 650-946 | Comcast | Internet / business phone carrier | – |
| 650-947 | AT&T (local phone) | Local phone company | – |
| 650-948 | AT&T (local phone) | Local phone company | – |
| 650-949 | AT&T (local phone) | Local phone company | – |
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.