Phone numbers in Castroville, Texas
Castroville has 6 phone prefixes in area code 830.
Biggest holders: AT&T (local phone), Telnyx, Teleport Communications America. This is the local calling area (rate center) where those prefixes were first assigned.
- Local phone company 33%
- Internet / business phone carrier 67%
Every prefix in Castroville
Search the first six digits of a number in this list. If it's here, the number started in Castroville with the carrier shown. If it isn't, check the Texas page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 830-346 | Telnyx | Internet / business phone carrier | 2017 |
| 830-349 | Teleport Communications America | Internet / business phone carrier | 2021 |
| 830-355 | Level 3 (Lumen) | Internet / business phone carrier | – |
| 830-521 | Matrix Telecom, Llc. S/i/i Tnci | Internet / business phone carrier | – |
| 830-538 | AT&T (local phone) | Local phone company | – |
| 830-931 | 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.