Phone numbers in Portsmouth, New Hampshire
Portsmouth has 28 phone prefixes in area code 603.
Biggest holders: Consolidated Comm Of No. New England-nh, Windstream (PAETEC), AT&T Mobility. This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 36%
- Local phone company 32%
- Internet / business phone carrier 29%
- Phone company 4%
Every prefix in Portsmouth
Search the first six digits of a number in this list. If it's here, the number started in Portsmouth with the carrier shown. If it isn't, check the New Hampshire page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 603-205 | T-Mobile (including Sprint) | Mobile carrier | – |
| 603-245 | Consolidated Comm Of No. New England-nh | Local phone company | – |
| 603-294 | Level 3 (Lumen) | Internet / business phone carrier | – |
| 603-319 | Windstream (PAETEC) | Internet / business phone carrier | – |
| 603-334 | Consolidated Comm Of No. New England-nh | Local phone company | – |
| 603-368 | Teleport Communications America | Internet / business phone carrier | 2017 |
| 603-373 | Windstream (PAETEC) | Internet / business phone carrier | – |
| 603-380 | AT&T Mobility | Mobile carrier | – |
| 603-422 | Consolidated Comm Of No. New England-nh | Local phone company | – |
| 603-427 | Consolidated Comm Of No. New England-nh | Local phone company | – |
| 603-430 | Consolidated Comm Of No. New England-nh | Local phone company | – |
| 603-431 | Consolidated Comm Of No. New England-nh | Local phone company | – |
| 603-433 | Consolidated Comm Of No. New England-nh | Local phone company | – |
| 603-436 | Consolidated Comm Of No. New England-nh | Local phone company | – |
| 603-498 | Bell Atlantic Mobile | Mobile carrier | – |
| 603-501 | Windstream (PAETEC) | Internet / business phone carrier | – |
| 603-502 | AT&T Mobility | Mobile carrier | – |
| 603-531 | AT&T Mobility | Mobile carrier | – |
| 603-559 | Consolidated Comm Of No. New England-nh | Local phone company | – |
| 603-570 | Teleport Communications America | Internet / business phone carrier | – |
| 603-610 | Windstream (PAETEC) | Internet / business phone carrier | – |
| 603-766 | Freedom Ring Communications | Phone company | – |
| 603-812 | Bell Atlantic Mobile | Mobile carrier | – |
| 603-828 | Bell Atlantic Mobile | Mobile carrier | 2002 |
| 603-956 | Vonage America | Internet / business phone carrier | 2022 |
| 603-957 | AT&T Mobility | Mobile carrier | 2002 |
| 603-969 | T-Mobile (including Sprint) | Mobile carrier | 2002 |
| 603-988 | T-Mobile (including Sprint) | Mobile carrier | 2001 |
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.