Connecticut, United States
Eastern Time
1:23 AM
Area Code
203
State / Province
Connecticut
Country
United States
Time Zone
Eastern Time
Area code 203 covers 32 cities and communities across Connecticut, based on telephone company rate center data.
Use the E.164 format for clickable phone links (RFC 3966):
<a href="tel:+12035550100">+12035550100</a><a href="tel:+12035550199">+12035550199</a>Look up which exchange in Connecticut a specific 203 number is homed to, and whether its block is wireline or wireless. See what a reverse lookup can establish before relying on the answer.
778 active prefixes in this area code, assigned as 5,494 thousands-blocks — pooling splits one prefix across several carriers, so each block is listed separately with the rate centre it is homed to, its carrier of record, and the switch that serves it.
Showing blocks 1–100 of 5,494
| NPA-NXX | Block | Rate centre | Type | Carrier (OCN) | Switch | LATA | LIR | Dates |
|---|---|---|---|---|---|---|---|---|
| 203-200 | 0 | New Haven | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - CT (199F) | HRFRCT0379Z | 920 | — | — |
| 203-200 | 1 | New Haven | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | New Haven, CT | 920 | — | — |
| 203-200 | 2 | New Haven | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | New Haven, CT | 920 | — | — |
| 203-200 | 3 | New Haven | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | New Haven, CT | 920 | — | — |
| 203-200 | 4 | New Haven | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | New Haven, CT | 920 | — | — |
| 203-200 | 5 | New Haven | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | New Haven, CT | 920 | — | — |
| 203-200 | 6 | New Haven | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | New Haven, CT | 920 | — | — |
| 203-200 | 7 | New Haven | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - CT (199F) | HRFRCT0379Z | 920 | — | — |
| 203-200 | 8 | New Haven | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT (6388) | HRFRCTASBMD | 920 | — | — |
| 203-200 | 9 | New Haven | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT (6388) | HRFRCTASBMD | 920 | — | — |
| 203-200 | A | New Haven | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - CT (199F) | HRFRCT0379Z | 920 | — | — |
| 203-201 | A | New Haven | Landline or VoIP | SPOK, INC. (6630) | BRPTCT23AMD | 920 | — | — |
| 203-202 | 0 | Darien | Landline or VoIP | ONVOY, LLC - CT (639C) | HARTFORD | 920 | — | — |
| 203-202 | 1 | Darien | Wireless | ONVOY SPECTRUM, LLC (624H) | NWHNCT02XJX | 920 | — | — |
| 203-202 | 2 | Darien | Landline or VoIP | CABLEVISION LIGHTPATH, INC. - CT (4950) | NRWLCT02YMD | 920 | — | — |
| 203-202 | 3 | Darien | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CT (4800) | SMFRCTPU4MD | 920 | — | — |
| 203-202 | 4 | Darien | Landline or VoIP | METROPCS, INC. (5562) | BLFDCTAP2MD | 920 | — | — |
| 203-202 | 5 | Darien | Wireless | ONVOY SPECTRUM, LLC (624H) | NWHNCT02XJX | 920 | — | — |
| 203-202 | 6 | Darien | Landline or VoIP | CABLEVISION LIGHTPATH, INC. - CT (4950) | NRWLCT02YMD | 920 | — | — |
| 203-202 | 7 | Darien | Landline or VoIP | CSC VOICE, LLC (612K) | NRWLCT02SMD | 920 | — | — |
| 203-202 | 8 | Darien | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT (7230) | STAMFORD | 920 | — | — |
| 203-202 | 9 | Darien | Landline or VoIP | CSC VOICE, LLC (612K) | NRWLCT02SMD | 920 | — | — |
| 203-202 | A | Darien | Landline or VoIP | CABLEVISION LIGHTPATH, INC. - CT (4950) | NRWLCT02YMD | 920 | — | — |
| 203-203 | 0 | Greenwich | Landline or VoIP | ONVOY, LLC - CT (639C) | MANHATTAN | 132 | — | — |
| 203-203 | 1 | Greenwich | Landline or VoIP | ONVOY, LLC - CT (639C) | MANHATTAN | 132 | — | — |
| 203-203 | 2 | Greenwich | Landline or VoIP | ONVOY, LLC - CT (639C) | MANHATTAN | 132 | — | — |
| 203-203 | 3 | Greenwich | Landline or VoIP | ONVOY, LLC - CT (639C) | MANHATTAN | 132 | — | — |
| 203-203 | 4 | Greenwich | Landline or VoIP | ONVOY, LLC - CT (639C) | MANHATTAN | 132 | — | — |
| 203-203 | 5 | Greenwich | Landline or VoIP | ONVOY, LLC - CT (639C) | MANHATTAN | 132 | — | — |
| 203-203 | 6 | Greenwich | Landline or VoIP | ONVOY, LLC - CT (639C) | MANHATTAN | 132 | — | — |
| 203-203 | 7 | Greenwich | Landline or VoIP | ONVOY, LLC - CT (639C) | MANHATTAN | 132 | — | — |
| 203-203 | 8 | Greenwich | Landline or VoIP | ONVOY, LLC - CT (639C) | MANHATTAN | 132 | — | — |
| 203-203 | 9 | Greenwich | Landline or VoIP | ONVOY, LLC - CT (639C) | MANHATTAN | 132 | — | — |
| 203-203 | A | Greenwich | Landline or VoIP | ONVOY, LLC - CT (639C) | MANHATTAN | 132 | — | — |
| 203-204 | 0 | Guilford | Landline or VoIP | TELEPORT COMMUNICATIONS AMERICA, LLC - CT (7143) | HARTFORD | 920 | — | — |
| 203-204 | 1 | Guilford | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CT (4800) | SMFRCTPU4MD | 920 | — | — |
| 203-204 | 2 | Guilford | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CT (4800) | SMFRCTPU4MD | 920 | — | — |
| 203-204 | 3 | Guilford | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - CT (199F) | HRFRCT0379Z | 920 | — | — |
| 203-204 | 4 | Guilford | Landline or VoIP | ONVOY, LLC - CT (639C) | HARTFORD | 920 | — | — |
| 203-204 | 5 | Guilford | Landline or VoIP | ONVOY, LLC - CT (639C) | HARTFORD | 920 | — | — |
| 203-204 | 6 | Guilford | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CT (4800) | SMFRCTPU4MD | 920 | — | — |
| 203-204 | 7 | Guilford | Landline or VoIP | ONVOY, LLC - CT (639C) | HARTFORD | 920 | — | — |
| 203-204 | 8 | Guilford | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - CT (199F) | HRFRCT0379Z | 920 | — | — |
| 203-204 | 9 | Guilford | Landline or VoIP | ONVOY, LLC - CT (639C) | HARTFORD | 920 | — | — |
| 203-204 | A | Guilford | Landline or VoIP | TELEPORT COMMUNICATIONS AMERICA, LLC - CT (7143) | HARTFORD | 920 | — | — |
| 203-205 | 0 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-205 | 1 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-205 | 2 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-205 | 3 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-205 | 4 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-205 | 5 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-205 | 6 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-205 | 7 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-205 | 8 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-205 | 9 | Danbury | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CT (4800) | SMFRCTPU4MD | 920 | — | — |
| 203-205 | A | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-206 | A | Waterbury | Wireless | NEW CINGULAR WIRELESS PCS, LLC - DC (4036) | MDTWCTNIBMD | 920 | — | — |
| 203-207 | 0 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-207 | 1 | Danbury | Wireless | NEW CINGULAR WIRELESS PCS, LLC - DC (4036) | MDTWCTNIBMD | 920 | — | — |
| 203-207 | 2 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-207 | 3 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-207 | 4 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-207 | 5 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-207 | 6 | Danbury | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT (7230) | STAMFORD | 920 | — | — |
| 203-207 | 7 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-207 | 8 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-207 | 9 | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-207 | A | Danbury | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | Danbury, CT | 920 | — | — |
| 203-208 | 0 | Branford | Landline or VoIP | COMCAST IP PHONE, LLC (318J) | HRFRCTCR3MD | 920 | — | — |
| 203-208 | 1 | Branford | Landline or VoIP | COMCAST IP PHONE, LLC (318J) | HRFRCTCR3MD | 920 | — | — |
| 203-208 | 2 | Branford | Landline or VoIP | COMCAST IP PHONE, LLC (318J) | HRFRCTCR3MD | 920 | — | — |
| 203-208 | 3 | Branford | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CT (4800) | SMFRCTPU4MD | 920 | — | — |
| 203-208 | 4 | Branford | Landline or VoIP | COMCAST IP PHONE, LLC (318J) | HRFRCTCR3MD | 920 | — | — |
| 203-208 | 5 | Branford | Landline | SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (9147) | NWHNCT02GT0 | 920 | — | — |
| 203-208 | 6 | Branford | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - CT (199F) | HRFRCT0379Z | 920 | — | — |
| 203-208 | 7 | Branford | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - CT (199F) | HRFRCT0379Z | 920 | — | — |
| 203-208 | 8 | Branford | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - CT (199F) | HRFRCT0379Z | 920 | — | — |
| 203-208 | 9 | Branford | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - CT (199F) | HRFRCT0379Z | 920 | — | — |
| 203-208 | A | Branford | Landline or VoIP | COMCAST IP PHONE, LLC (318J) | HRFRCTCR3MD | 920 | — | — |
| 203-209 | A | Bridgeport | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT (6388) | HRFRCTASBMD | 920 | — | — |
| 203-210 | 0 | Wilton | Landline or VoIP | CABLEVISION LIGHTPATH, INC. - CT (4950) | NRWLCT02YMD | 920 | — | — |
| 203-210 | 1 | Wilton | Landline or VoIP | CABLEVISION LIGHTPATH, INC. - CT (4950) | NRWLCT02YMD | 920 | — | — |
| 203-210 | 2 | Wilton | Landline or VoIP | CABLEVISION LIGHTPATH, INC. - CT (4950) | NRWLCT02YMD | 920 | — | — |
| 203-210 | 3 | Wilton | Landline or VoIP | CABLEVISION LIGHTPATH, INC. - CT (4950) | NRWLCT02YMD | 920 | — | — |
| 203-210 | 4 | Wilton | Landline or VoIP | CABLEVISION LIGHTPATH, INC. - CT (4950) | NRWLCT02YMD | 920 | — | — |
| 203-210 | 5 | Wilton | Landline or VoIP | CSC VOICE, LLC (612K) | NRWLCT02SMD | 920 | — | — |
| 203-210 | 6 | Wilton | Landline or VoIP | CABLEVISION LIGHTPATH, INC. - CT (4950) | NRWLCT02YMD | 920 | — | — |
| 203-210 | 7 | Wilton | Landline or VoIP | CSC VOICE, LLC (612K) | NRWLCT02SMD | 920 | — | — |
| 203-210 | 8 | Wilton | Landline or VoIP | ONVOY, LLC - CT (639C) | HARTFORD | 920 | — | — |
| 203-210 | 9 | Wilton | Landline or VoIP | CABLEVISION LIGHTPATH, INC. - CT (4950) | NRWLCT02YMD | 920 | — | — |
| 203-210 | A | Wilton | Landline or VoIP | CABLEVISION LIGHTPATH, INC. - CT (4950) | NRWLCT02YMD | 920 | — | — |
| 203-212 | 0 | Bridgeport | Wireless | NEW CINGULAR WIRELESS PCS, LLC - DC (4036) | MDTWCTNIBMD | 920 | — | — |
| 203-212 | 1 | Bridgeport | Wireless | NEW CINGULAR WIRELESS PCS, LLC - DC (4036) | MDTWCTNIBMD | 920 | — | — |
| 203-212 | 2 | Bridgeport | Landline or VoIP | METROPCS, INC. (5562) | BLFDCTAP2MD | 920 | — | — |
| 203-212 | 3 | Bridgeport | Landline or VoIP | CSC VOICE, LLC (612K) | NRWLCT02SMD | 920 | — | — |
| 203-212 | 4 | Bridgeport | Wireless | NEW CINGULAR WIRELESS PCS, LLC - DC (4036) | MDTWCTNIBMD | 920 | — | — |
| 203-212 | 5 | Bridgeport | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT (7230) | STAMFORD | 920 | — | — |
| 203-212 | 6 | Bridgeport | Wireless | NEW CINGULAR WIRELESS PCS, LLC - DC (4036) | MDTWCTNIBMD | 920 | — | — |
| 203-212 | 7 | Bridgeport | Wireless | NEW CINGULAR WIRELESS PCS, LLC - DC (4036) | MDTWCTNIBMD | 920 | — | — |
| 203-212 | 8 | Bridgeport | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - CT (199F) | HRFRCT0379Z | 920 | — | — |
Block-level assignments from the North American Numbering Plan administrator, via localcallingguide.com.
Assigned Prefixes
778
Assignment Blocks
5,494
Rate Centers
32
Carriers of Record
34
| Type | Blocks | Share |
|---|---|---|
| Landline | 1,338 | 24% |
| Landline or VoIP | 2,659 | 48% |
| Wireless | 1,497 | 27% |
| Carrier | Blocks |
|---|---|
| SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | 1,282 |
| OMNIPOINT COMMUNICATIONS, INC. - CT | 549 |
| CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT | 523 |
| PAETEC ITEL, LLC | 393 |
| NEW CINGULAR WIRELESS PCS, LLC - DC | 373 |
| METROPCS, INC. | 335 |
| MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT | 324 |
| BANDWIDTH.COM CLEC, LLC - CT | 319 |
| LEVEL 3 COMMUNICATIONS, LLC - CT | 302 |
| CABLEVISION LIGHTPATH, INC. - CT | 192 |
| 24 other carriers | 902 |
Carrier of record for each block. Numbers ported to another carrier keep their original block assignment, so this is not a lookup of who serves a given number today.
| Rate Center | Prefixes | Blocks |
|---|---|---|
| New Haven | 145 | 875 |
| Stamford | 97 | 737 |
| Bridgeport | 94 | 624 |
| Norwalk | 60 | 400 |
| Danbury | 54 | 351 |
| Waterbury | 52 | 352 |
| Greenwich | 27 | 207 |
| Meriden | 24 | 164 |
| Ansonia-Derby | 17 | 136 |
| Westport | 16 | 106 |
| Darien | 15 | 135 |
| Fairfield | 15 | 114 |
| Huntington | 14 | 94 |
| Milford | 14 | 84 |
| Wallingford | 14 | 104 |
| Trumbull | 13 | 92 |
| Branford | 10 | 69 |
| Cheshire | 10 | 80 |
| New Canaan | 9 | 77 |
| Old Greenwich | 9 | 88 |
| Byram | 8 | 77 |
| Guilford | 8 | 68 |
| Wilton | 8 | 68 |
| Woodbury | 8 | 78 |
| Madison | 6 | 56 |
| Naugatuck | 6 | 56 |
| Newtown | 5 | 35 |
| Ridgefield | 5 | 35 |
| Seymour | 5 | 44 |
| Wolcott | 4 | 34 |
| Georgetown | 3 | 33 |
| Redding | 3 | 21 |
A rate center is the telephone exchange area a number is homed to. It sets local calling boundaries, and is not the caller's current location.
Area code 203 is a North American Numbering Plan (NANP) telephone area code assigned to Connecticut, United States. It is one of 4 area codes serving Connecticut. As population and demand for phone numbers grew, the region was divided into multiple numbering plan areas to avoid exhausting the available 7-digit number pool.
Yes. 203 is an active North American Numbering Plan (NANP) area code, currently assigned to Connecticut, United States. It is safe to answer or dial calls using this area code.
Area code 203 covers 32 cities and communities in Connecticut, including Ansonia-Derby, Branford, Bridgeport, Byram, Cheshire, and 27 more localities. This is based on telephone company rate center data — the geographic areas carriers use to determine local calling boundaries and to assign numbers when a business or individual requests a phone number in a specific city.
All numbers in the 203 area code observe Eastern Time (IANA timezone: America/New_York). Eastern Time is UTC−5 in winter (EST) and UTC−4 in summer (EDT). When placing a call to a 203 number from a different time zone, check the current local time above to avoid calling outside of business hours.
From within Connecticut, dial the 7-digit local number directly if calling within the same rate center, or dial 1 + 203 + 7-digit number for long-distance calls within North America. From outside the US or Canada, dial your country's international exit code followed by 1 203 XXX XXXX. The country code for both the United States and Canada in NANP is +1.
Format 203 numbers using E.164 notation as required by RFC 3966: prefix with +1 and omit dashes and parentheses (e.g., +12035550100). This format ensures tel: links work correctly on all mobile browsers and VoIP apps. See the tel: URI formatting guide for complete examples.