Phone numbers in Greenwich, Connecticut
Greenwich has 35 phone prefixes in area codes 203, 475.
Biggest holders: Verizon (local phone), Cablevision Lightpath, Onvoy. This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 3%
- Local phone company 34%
- Internet / business phone carrier 57%
- Phone company 6%
Every prefix in Greenwich
Search the first six digits of a number in this list. If it's here, the number started in Greenwich with the carrier shown. If it isn't, check the Connecticut page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 203-203 | Onvoy | Internet / business phone carrier | 2024 |
| 203-302 | Tc Systems | Phone company | – |
| 203-340 | Cablevision Lightpath | Internet / business phone carrier | 2003 |
| 203-413 | Windstream (PAETEC) | Internet / business phone carrier | – |
| 203-422 | Verizon (local phone) | Local phone company | – |
| 203-485 | Cablevision Lightpath | Internet / business phone carrier | – |
| 203-489 | Cablevision Lightpath | Internet / business phone carrier | 2011 |
| 203-496 | MetroPCS (T-Mobile) | Mobile carrier | – |
| 203-542 | AT&T (local phone) | Local phone company | – |
| 203-618 | Verizon (local phone) | Local phone company | – |
| 203-622 | Verizon (local phone) | Local phone company | – |
| 203-625 | Verizon (local phone) | Local phone company | – |
| 203-629 | Verizon (local phone) | Local phone company | – |
| 203-661 | Verizon (local phone) | Local phone company | – |
| 203-717 | Csc Voice | Internet / business phone carrier | 2011 |
| 203-742 | MCImetro (Verizon Business) | Internet / business phone carrier | 2003 |
| 203-769 | Verizon (local phone) | Local phone company | – |
| 203-861 | Verizon (local phone) | Local phone company | – |
| 203-862 | Verizon (local phone) | Local phone company | – |
| 203-863 | Verizon (local phone) | Local phone company | – |
| 203-869 | Verizon (local phone) | Local phone company | – |
| 203-900 | Csc Voice | Internet / business phone carrier | 2012 |
| 203-930 | Level 3 (Lumen) | Internet / business phone carrier | 2001 |
| 203-971 | Cablevision Lightpath | Internet / business phone carrier | – |
| 203-983 | Windstream (PAETEC) | Internet / business phone carrier | – |
| 203-987 | Level 3 (Lumen) | Internet / business phone carrier | 2001 |
| 203-992 | Csc Voice | Internet / business phone carrier | 2006 |
| 475-240 | Tc Systems | Phone company | 2015 |
| 475-278 | Cablevision Lightpath | Internet / business phone carrier | 2021 |
| 475-303 | Nuso | Internet / business phone carrier | 2020 |
| 475-335 | Onvoy | Internet / business phone carrier | 2023 |
| 475-383 | Onvoy | Internet / business phone carrier | 2024 |
| 475-500 | Onvoy | Internet / business phone carrier | 2019 |
| 475-509 | Cablevision Lightpath | Internet / business phone carrier | 2026 |
| 475-897 | Csc Voice | Internet / business phone carrier | 2015 |
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.