Verified Nov 1, 2026 · Source: NANPA CO Code Assignment Records
STAMFORD prefixes in area code 203
NANPA records 97 assigned NXX blocks to rate center STAMFORD in area code 203, 12.4% of the 784 blocks assigned in the code. A rate center is the billing geography a block is allocated to – NANPA truncates the name to ten characters, so read it as a NANPA label rather than a town. 13 holders hold those blocks, the largest being SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (49), MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT (9), NEW CINGULAR WIRELESS PCS, LLC - DC (7). The earliest assignment on record here is 2001-01-03 and the most recent 2012-02-24. 64 of them are in thousands-block pooling, so those prefixes are shared between carriers in 1,000-number lots. The same rate center name also appears in area codes 308, 325, 475, 607 – overlay codes cover the same geography, so a rate center is served by all of them.
97 assigned blocks – 12.4% of 203
13 holders of record
64 of them pooled in 1,000-number lots
Prefixes assigned here
| Prefix | Holder of record | Assigned | Pooled | In service |
|---|---|---|---|---|
| 203-219 | AT&T NEW CINGULAR WIRELESS PCS, LLC - DC | – | no | yes |
| 203-223 | T-Mobile OMNIPOINT COMMUNICATIONS, INC. - CT | – | yes | yes |
| 203-249 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT | – | no | yes |
| 203-251 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-252 | Altice CABLEVISION LIGHTPATH, INC. - CT | – | yes | yes |
| 203-253 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT | – | no | yes |
| 203-273 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT | 2002-10-22 | yes | yes |
| 203-274 | AT&T NEW CINGULAR WIRELESS PCS, LLC - DC | – | yes | yes |
| 203-276 | Altice CABLEVISION LIGHTPATH, INC. - CT | 2003-03-28 | yes | yes |
| 203-282 | Spok SPOK, INC. | – | no | yes |
| 203-316 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-321 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-322 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-323 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-324 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-325 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-326 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-327 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-328 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-329 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-348 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-351 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-352 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-353 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-355 | Altice CABLEVISION LIGHTPATH, INC. - CT | – | no | yes |
| 203-356 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-357 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-358 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-359 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-363 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-388 | Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT | – | yes | yes |
| 203-391 | Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT | – | yes | yes |
| 203-399 | Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT | – | yes | yes |
| 203-406 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-425 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-428 | Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT | – | yes | yes |
| 203-461 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-462 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-487 | Lumen LEVEL 3 COMMUNICATIONS, LLC - CT | 2001-01-03 | yes | yes |
| 203-504 | Windstream PAETEC ITEL, LLC | 2004-02-12 | yes | yes |
| 203-517 | Lumen LEVEL 3 COMMUNICATIONS, LLC - CT | – | yes | yes |
| 203-524 | AT&T NEW CINGULAR WIRELESS PCS, LLC - DC | – | yes | yes |
| 203-536 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT | – | no | yes |
| 203-539 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-541 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-547 | Onvoy ONVOY, LLC - CT | – | no | yes |
| 203-548 | Lumen LEVEL 3 COMMUNICATIONS, LLC - CT | 2002-05-30 | yes | yes |
| 203-550 | T-Mobile OMNIPOINT COMMUNICATIONS, INC. - CT | – | no | yes |
| 203-554 | AT&T NEW CINGULAR WIRELESS PCS, LLC - DC | – | no | yes |
| 203-561 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT | – | no | yes |
| 203-564 | AT&T AT&T - LOCAL | – | yes | yes |
| 203-566 | Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT | 2003-02-04 | yes | yes |
| 203-569 | Altice CABLEVISION LIGHTPATH, INC. - CT | – | yes | yes |
| 203-570 | T-Mobile OMNIPOINT COMMUNICATIONS, INC. - CT | 2001-03-26 | no | yes |
| 203-585 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-588 | Altice CABLEVISION LIGHTPATH, INC. - CT | – | yes | yes |
| 203-595 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-602 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-607 | Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT | 2003-02-04 | yes | yes |
| 203-609 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-614 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-653 | Windstream PAETEC ITEL, LLC | – | yes | yes |
| 203-658 | AT&T TELEPORT COMMUNICATIONS AMERICA, LLC - CT | – | yes | yes |
| 203-667 | T-Mobile OMNIPOINT COMMUNICATIONS, INC. - CT | – | yes | yes |
| 203-674 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-703 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-705 | Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT | – | yes | yes |
| 203-708 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-719 | Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT | – | no | yes |
| 203-724 | Windstream PAETEC ITEL, LLC | – | yes | yes |
| 203-728 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | 2006-11-22 | yes | yes |
| 203-817 | Altice CABLEVISION LIGHTPATH, INC. - CT | – | yes | yes |
| 203-832 | AT&T NEW CINGULAR WIRELESS PCS, LLC - DC | 2006-04-06 | yes | yes |
| 203-883 | Lumen LEVEL 3 COMMUNICATIONS, LLC - CT | – | yes | yes |
| 203-890 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | 2001-07-27 | yes | yes |
| 203-897 | Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT | 2008-08-20 | yes | yes |
| 203-905 | AT&T TELEPORT COMMUNICATIONS AMERICA, LLC - CT | – | yes | yes |
| 203-912 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT | – | no | yes |
| 203-914 | CSC VOICE, LLC | 2012-02-24 | yes | yes |
| 203-918 | AT&T NEW CINGULAR WIRELESS PCS, LLC - DC | – | no | yes |
| 203-921 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-940 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-960 | Altice CABLEVISION LIGHTPATH, INC. - CT | 2008-09-15 | yes | yes |
| 203-961 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-962 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-964 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-965 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-967 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-968 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-969 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-973 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-975 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-977 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | no | yes |
| 203-978 | AT&T SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | – | yes | yes |
| 203-979 | AT&T NEW CINGULAR WIRELESS PCS, LLC - DC | – | no | yes |
| 203-989 | Lumen LEVEL 3 COMMUNICATIONS, LLC - CT | – | yes | yes |
| 203-998 | Lumen LEVEL 3 COMMUNICATIONS, LLC - CT | 2004-10-15 | yes | yes |
The holder is who received the block from the numbering administrator. It is not necessarily the carrier serving a given number: numbers move with their owners, and a pooled block is shared.
Who holds the blocks
| Holder | Brand | Blocks | Share here |
|---|---|---|---|
| SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | AT&T | 49 | 50.5% |
| MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT | Verizon | 9 | 9.3% |
| NEW CINGULAR WIRELESS PCS, LLC - DC | AT&T | 7 | 7.2% |
| CABLEVISION LIGHTPATH, INC. - CT | Altice | 7 | 7.2% |
| CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT | Verizon | 6 | 6.2% |
| LEVEL 3 COMMUNICATIONS, LLC - CT | Lumen | 6 | 6.2% |
| OMNIPOINT COMMUNICATIONS, INC. - CT | T-Mobile | 4 | 4.1% |
| PAETEC ITEL, LLC | Windstream | 3 | 3.1% |
| TELEPORT COMMUNICATIONS AMERICA, LLC - CT | AT&T | 2 | 2.1% |
| SPOK, INC. | Spok | 1 | 1% |
| ONVOY, LLC - CT | Onvoy | 1 | 1% |
| AT&T - LOCAL | AT&T | 1 | 1% |
| CSC VOICE, LLC | – | 1 | 1% |
Same rate center in other codes
Overlay codes cover the same geography, so one rate center is served by all of them.
Frequently asked
Which prefixes belong to STAMFORD in area code 203?
97 blocks: 219, 223, 249, 251, 252, 253, 273, 274, 276, 282, 316, 321 and 85 more, all listed in the table above.
Which carriers have numbers in STAMFORD?
SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (49 blocks), MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT (9 blocks), NEW CINGULAR WIRELESS PCS, LLC - DC (7 blocks), CABLEVISION LIGHTPATH, INC. - CT (7 blocks), CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT (6 blocks), LEVEL 3 COMMUNICATIONS, LLC - CT (6 blocks). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.
Is STAMFORD a city?
It is a rate center – the unit NANPA allocates number blocks to. Its name is abbreviated to ten characters and is not necessarily a settlement: we print it as recorded rather than guess at the full name.