Phone numbers in Iowa, Louisiana
Iowa has 5 phone prefixes in area code 337.
Biggest holders: AT&T Mobility, MetroPCS (T-Mobile), T-Mobile (including Sprint). This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 60%
- Local phone company 20%
- Internet / business phone carrier 20%
Every prefix in Iowa
Search the first six digits of a number in this list. If it's here, the number started in Iowa with the carrier shown. If it isn't, check the Louisiana page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 337-358 | AT&T Mobility | Mobile carrier | 2004 |
| 337-379 | MetroPCS (T-Mobile) | Mobile carrier | 2004 |
| 337-391 | T-Mobile (including Sprint) | Mobile carrier | 2004 |
| 337-582 | Brightspeed Of Louisiana | Local phone company | – |
| 337-610 | Commio | Internet / business phone carrier | 2023 |
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.