Area code 557: where it is and who calls from it
Area code 557 is in Missouri.
Missouri (St. Louis, St. Louis County, Florissant, Crestwood, Hazelwood, Kirkwood, and surrounding suburbs of St. Louis)
| Where | Missouri |
|---|---|
| Time zone | Central Time ยท local time |
| In service since | 2022 |
| Overlay | Yes, with 314 |
| Prefixes assigned | 84 of 792 possible (11%) |
Overlay: 557 covers the same area as 314. Overlay areas use 10-digit dialing, so a seven-digit number alone won't connect, and neighbors can have different area codes.
Where 557 numbers started
Every prefix is assigned to a rate center, the local calling area it was set up in. These are the biggest in 557, with how many prefixes each has.
Who holds 557 numbers
- Mobile carrier 40%
- Internet / business phone carrier 50%
- Phone company 10%
| Carrier | Type | Prefixes | Share |
|---|---|---|---|
| AT&T Mobility | Mobile carrier | 23 | 27% |
| Onvoy | Internet / business phone carrier | 22 | 26% |
| Teleport Communications America | Internet / business phone carrier | 15 | 18% |
| Verizon Wireless | Mobile carrier | 8 | 10% |
| T-Mobile (including Sprint) | Mobile carrier | 2 | 2% |
| FIVE9 | Phone company | 2 | 2% |
| Terra Nova Telecom | Internet / business phone carrier | 2 | 2% |
| Comcast | Internet / business phone carrier | 1 | 1% |
| Callworks | Phone company | 1 | 1% |
| Leap Telecom | Phone company | 1 | 1% |
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.
States served: Missouri.
Other area codes in Missouri
235 314 417 573 636 660 816 975
Got a call from 557?
An area code tells you where a number was first assigned, not where the caller is. People keep their numbers when they move, and scammers can fake any number. If you weren't expecting the call, let it go to voicemail.
If the call shows a 557 number that matches the first six digits of your own, that's often neighbor spoofing. Use the box above to check the full number.
Area code facts from the NANPA area code database (updated 10/06/2026); prefixes and carriers from NANPA's central office code records (updated 2026-10-10). Place description adapted from Wikipedia, CC BY-SA 4.0.