Phone numbers in Port Isabel, Texas
Port Isabel has 8 phone prefixes in area code 956.
Biggest holders: AT&T (local phone), Stpcs Joint Venture, Onvoy. This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 38%
- Local phone company 38%
- Internet / business phone carrier 25%
Every prefix in Port Isabel
Search the first six digits of a number in this list. If it's here, the number started in Port Isabel with the carrier shown. If it isn't, check the Texas page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 956-299 | Stpcs Joint Venture | Mobile carrier | 2002 |
| 956-426 | Onvoy | Internet / business phone carrier | 2017 |
| 956-433 | Stpcs Joint Venture | Mobile carrier | 2002 |
| 956-524 | MetroPCS (T-Mobile) | Mobile carrier | 2007 |
| 956-697 | Onvoy | Internet / business phone carrier | 2021 |
| 956-761 | AT&T (local phone) | Local phone company | – |
| 956-772 | AT&T (local phone) | Local phone company | – |
| 956-943 | 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.