Phone numbers in Prosser, Washington
Prosser has 6 phone prefixes in area code 509.
Biggest holders: CenturyLink / Lumen, T-Mobile (including Sprint), Level 3 (Lumen). This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 50%
- Local phone company 33%
- Internet / business phone carrier 17%
Every prefix in Prosser
Search the first six digits of a number in this list. If it's here, the number started in Prosser with the carrier shown. If it isn't, check the Washington page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 509-303 | T-Mobile (including Sprint) | Mobile carrier | – |
| 509-778 | Level 3 (Lumen) | Internet / business phone carrier | 2002 |
| 509-781 | AT&T Mobility | Mobile carrier | – |
| 509-786 | CenturyLink / Lumen | Local phone company | – |
| 509-788 | CenturyLink / Lumen | Local phone company | – |
| 509-832 | UScellular | Mobile carrier | – |
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.