Phone numbers in San Juan, California
San Juan has 4 phone prefixes in area code 831.
Biggest holders: Peerless Network Of California, IP Horizon, Charter / Spectrum. This is the local calling area (rate center) where those prefixes were first assigned.
- Local phone company 25%
- Internet / business phone carrier 75%
Every prefix in San Juan
Search the first six digits of a number in this list. If it's here, the number started in San Juan with the carrier shown. If it isn't, check the California page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 831-301 | Peerless Network Of California | Internet / business phone carrier | – |
| 831-586 | IP Horizon | Internet / business phone carrier | – |
| 831-593 | Charter / Spectrum | Internet / business phone carrier | – |
| 831-623 | 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.