Phone numbers in Clemson, South Carolina
Clemson has 17 phone prefixes in area codes 821, 864.
Biggest holders: AT&T (local phone), Onvoy, Windstream (PAETEC). This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 29%
- Local phone company 29%
- Internet / business phone carrier 41%
Every prefix in Clemson
Search the first six digits of a number in this list. If it's here, the number started in Clemson with the carrier shown. If it isn't, check the South Carolina page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 821-888 | Onvoy | Internet / business phone carrier | 2025 |
| 864-533 | Verizon Wireless | Mobile carrier | 2018 |
| 864-623 | Windstream (PAETEC) | Internet / business phone carrier | – |
| 864-624 | AT&T (local phone) | Local phone company | – |
| 864-633 | Windstream (PAETEC) | Internet / business phone carrier | – |
| 864-635 | Onvoy | Internet / business phone carrier | 2018 |
| 864-643 | Level 3 (Lumen) | Internet / business phone carrier | 2001 |
| 864-650 | AT&T Mobility | Mobile carrier | – |
| 864-653 | AT&T (local phone) | Local phone company | – |
| 864-654 | AT&T (local phone) | Local phone company | – |
| 864-656 | AT&T (local phone) | Local phone company | – |
| 864-722 | Windstream (PAETEC) | Internet / business phone carrier | 2002 |
| 864-780 | Onvoy | Internet / business phone carrier | 2021 |
| 864-795 | Verizon Wireless | Mobile carrier | 2022 |
| 864-858 | AT&T (local phone) | Local phone company | – |
| 864-925 | AT&T Mobility | Mobile carrier | 2024 |
| 864-986 | MetroPCS (T-Mobile) | Mobile carrier | 2002 |
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.