Phone numbers in El Rio, California
El Rio has 18 phone prefixes in area codes 805, 820.
Biggest holders: Frontier, Onvoy, Bandwidth. This is the local calling area (rate center) where those prefixes were first assigned.
- Local phone company 44%
- Internet / business phone carrier 56%
Every prefix in El Rio
Search the first six digits of a number in this list. If it's here, the number started in El Rio with the carrier shown. If it isn't, check the California page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 805-278 | Frontier | Local phone company | – |
| 805-288 | Onvoy | Internet / business phone carrier | – |
| 805-307 | Bandwidth | Internet / business phone carrier | 2015 |
| 805-351 | Frontier | Local phone company | – |
| 805-485 | Frontier | Local phone company | – |
| 805-604 | Frontier | Local phone company | – |
| 805-718 | Teleport Communications America | Internet / business phone carrier | 2017 |
| 805-751 | Tpx Communications | Internet / business phone carrier | – |
| 805-790 | Bandwidth | Internet / business phone carrier | 2019 |
| 805-919 | Level 3 (Lumen) | Internet / business phone carrier | – |
| 805-973 | AT&T (local phone) | Local phone company | – |
| 805-974 | Bandwidth | Internet / business phone carrier | 2022 |
| 805-981 | Frontier | Local phone company | – |
| 805-983 | Frontier | Local phone company | – |
| 805-988 | Frontier | Local phone company | – |
| 820-226 | Onvoy | Internet / business phone carrier | 2024 |
| 820-242 | Onvoy | Internet / business phone carrier | 2025 |
| 820-345 | Fractel | Internet / business phone carrier | 2020 |
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.