Phone numbers in Clayton, California
Clayton has 12 phone prefixes in area code 925.
Biggest holders: AT&T (local phone), MCImetro (Verizon Business), T-Mobile (including Sprint). This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 17%
- Local phone company 25%
- Internet / business phone carrier 58%
Every prefix in Clayton
Search the first six digits of a number in this list. If it's here, the number started in Clayton with the carrier shown. If it isn't, check the California page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 925-276 | MCImetro (Verizon Business) | Internet / business phone carrier | – |
| 925-304 | Level 3 (Lumen) | Internet / business phone carrier | – |
| 925-524 | AT&T (local phone) | Local phone company | – |
| 925-567 | T-Mobile (including Sprint) | Mobile carrier | 2001 |
| 925-672 | AT&T (local phone) | Local phone company | – |
| 925-673 | AT&T (local phone) | Local phone company | – |
| 925-690 | MCImetro (Verizon Business) | Internet / business phone carrier | – |
| 925-693 | Teleport Communications America | Internet / business phone carrier | – |
| 925-844 | Tpx Communications | Internet / business phone carrier | 2001 |
| 925-889 | Matrix Telecom, Llc. S/i/i Tnci | Internet / business phone carrier | – |
| 925-914 | T-Mobile (including Sprint) | Mobile carrier | 2002 |
| 925-993 | Hd Carrier | Internet / business phone carrier | – |
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.