Phone numbers in Watertown, Massachusetts
Watertown has 21 phone prefixes in area codes 617, 857.
Biggest holders: Verizon (local phone), MCImetro (Verizon Business), Tc Systems. This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 5%
- Local phone company 24%
- Internet / business phone carrier 52%
- Phone company 19%
Every prefix in Watertown
Search the first six digits of a number in this list. If it's here, the number started in Watertown with the carrier shown. If it isn't, check the Massachusetts page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 617-231 | Level 3 (Lumen) | Internet / business phone carrier | – |
| 617-321 | Windstream (PAETEC) | Internet / business phone carrier | – |
| 617-393 | Rcn Telecom Services | Phone company | – |
| 617-402 | Peerless Network Of Massachusetts | Internet / business phone carrier | – |
| 617-458 | MetroPCS (T-Mobile) | Mobile carrier | 2002 |
| 617-600 | MCImetro (Verizon Business) | Internet / business phone carrier | – |
| 617-607 | MCImetro (Verizon Business) | Internet / business phone carrier | – |
| 617-612 | Tc Systems | Phone company | – |
| 617-668 | MCImetro (Verizon Business) | Internet / business phone carrier | – |
| 617-673 | Verizon (local phone) | Local phone company | – |
| 617-744 | Comcast | Internet / business phone carrier | – |
| 617-923 | Verizon (local phone) | Local phone company | – |
| 617-924 | Verizon (local phone) | Local phone company | – |
| 617-926 | Verizon (local phone) | Local phone company | – |
| 617-972 | Verizon (local phone) | Local phone company | – |
| 857-228 | Windstream (PAETEC) | Internet / business phone carrier | 2001 |
| 857-304 | Tc Systems | Phone company | 2013 |
| 857-367 | Tc Systems | Phone company | 2020 |
| 857-371 | Onvoy | Internet / business phone carrier | – |
| 857-737 | TON80 Communications | Internet / business phone carrier | 2022 |
| 857-760 | Bandwidth | Internet / business phone carrier | 2016 |
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.