Colorado, United States
Mountain Time
11:23 PM
Area Code
303
State / Province
Colorado
Country
United States
Time Zone
Mountain Time
Area code 303 covers 13 cities and communities across Colorado, based on telephone company rate center data.
Use the E.164 format for clickable phone links (RFC 3966):
<a href="tel:+13035550100">+13035550100</a><a href="tel:+13035550199">+13035550199</a>Look up which exchange in Colorado a specific 303 number is homed to, and whether its block is wireline or wireless. See what a reverse lookup can establish before relying on the answer.
785 active prefixes in this area code, assigned as 3,058 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 3,058
| NPA-NXX | Block | Rate centre | Type | Carrier (OCN) | Switch | LATA | LIR | Dates |
|---|---|---|---|---|---|---|---|---|
| 303-200 | 0 | Denver | Landline or VoIP | COMCAST IP PHONE, LLC (318J) | DNVRCOMA39Z | 656 | — | — |
| 303-200 | 1 | Denver | Landline or VoIP | TELEPORT COMMUNICATIONS AMERICA, LLC - CO (7378) | FTCLCOMAAMD | 656 | — | — |
| 303-200 | 2 | Denver | Landline or VoIP | TELEPORT COMMUNICATIONS AMERICA, LLC - CO (7378) | FTCLCOMAAMD | 656 | — | — |
| 303-200 | 3 | Denver | Landline or VoIP | TELEPORT COMMUNICATIONS AMERICA, LLC - CO (7378) | FTCLCOMAAMD | 656 | — | — |
| 303-200 | 4 | Denver | Landline or VoIP | TELEPORT COMMUNICATIONS AMERICA, LLC - CO (7378) | FTCLCOMAAMD | 656 | — | — |
| 303-200 | 5 | Denver | Landline or VoIP | TELEPORT COMMUNICATIONS AMERICA, LLC - CO (7378) | FTCLCOMAAMD | 656 | — | — |
| 303-200 | 6 | Denver | Landline or VoIP | TELEPORT COMMUNICATIONS AMERICA, LLC - CO (7378) | FTCLCOMAAMD | 656 | — | — |
| 303-200 | 7 | Denver | Landline or VoIP | TELEPORT COMMUNICATIONS AMERICA, LLC - CO (7378) | FTCLCOMAAMD | 656 | — | — |
| 303-200 | 8 | Denver | Landline or VoIP | TELEPORT COMMUNICATIONS AMERICA, LLC - CO (7378) | FTCLCOMAAMD | 656 | — | — |
| 303-200 | 9 | Denver | Landline or VoIP | TELEPORT COMMUNICATIONS AMERICA, LLC - CO (7378) | FTCLCOMAAMD | 656 | — | — |
| 303-200 | A | Denver | Landline or VoIP | TELEPORT COMMUNICATIONS AMERICA, LLC - CO (7378) | FTCLCOMAAMD | 656 | — | — |
| 303-201 | A | Denver | Landline or VoIP | SPOK, INC. (6630) | DNVRCOMAXTZ | 656 | — | — |
| 303-202 | A | Denver | Landline | QWEST CORPORATION (9636) | LKWD DGTL CAP HOST | 656 | — | — |
| 303-203 | A | Denver | Wireless | AMERICAN MESSAGING SERVICES, LLC (9748) | ENWDCOVF0MD | 656 | — | — |
| 303-204 | A | Denver | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CO (6567) | AURRCO20AMD | 656 | — | — |
| 303-205 | A | Denver | Landline | QWEST CORPORATION (9636) | LKWD DGTL CAP HOST | 656 | — | — |
| 303-206 | A | Denver | Landline or VoIP | SPOK, INC. (6630) | DNVRCOMAXTZ | 656 | — | — |
| 303-207 | A | Denver | Landline or VoIP | SPOK, INC. (6630) | DNVRCOMAXTZ | 656 | — | — |
| 303-208 | A | Denver | Landline or VoIP | SPOK, INC. (6630) | DNVRCOMAXTZ | 656 | — | — |
| 303-209 | A | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-210 | 0 | Denver | Wireless | T-MOBILE USA, INC. (6529) | DNVRCOII3MD | 656 | — | — |
| 303-210 | 1 | Denver | Wireless | T-MOBILE USA, INC. (6529) | DNVRCOII3MD | 656 | — | — |
| 303-210 | 2 | Denver | Wireless | T-MOBILE USA, INC. (6529) | DNVRCOII3MD | 656 | — | — |
| 303-210 | 3 | Denver | Wireless | T-MOBILE USA, INC. (6529) | DNVRCOII3MD | 656 | — | — |
| 303-210 | 4 | Denver | Wireless | T-MOBILE USA, INC. (6529) | DNVRCOII3MD | 656 | — | — |
| 303-210 | 5 | Denver | Wireless | T-MOBILE USA, INC. (6529) | DNVRCOII3MD | 656 | — | — |
| 303-210 | 6 | Denver | Wireless | T-MOBILE USA, INC. (6529) | DNVRCOII3MD | 656 | — | — |
| 303-210 | 7 | Denver | Wireless | T-MOBILE USA, INC. (6529) | DNVRCOII3MD | 656 | — | — |
| 303-210 | 8 | Denver | Wireless | T-MOBILE USA, INC. (6529) | DNVRCOII3MD | 656 | — | — |
| 303-210 | 9 | Denver | Wireless | T-MOBILE USA, INC. (6529) | DNVRCOII3MD | 656 | — | — |
| 303-210 | A | Denver | Wireless | T-MOBILE USA, INC. (6529) | DNVRCOII3MD | 656 | — | — |
| 303-212 | A | Denver | Wireless | AMERICAN MESSAGING SERVICES, LLC (9748) | ENWDCOVF0MD | 656 | — | — |
| 303-213 | A | Denver | Landline or VoIP | SPOK, INC. (6630) | DNVRCOMAXTZ | 656 | — | — |
| 303-214 | 0 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-214 | 1 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-214 | 2 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-214 | 3 | Denver | Landline or VoIP | PEERLESS NETWORK OF COLORADO, LLC - CO (278F) | DENVER | 656 | — | — |
| 303-214 | 4 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-214 | 5 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-214 | 6 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-214 | 7 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-214 | 8 | Denver | Wireless | T-MOBILE USA, INC. (6529) | DNVRCOII3MD | 656 | — | — |
| 303-214 | 9 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-214 | A | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-215 | A | Denver | Landline | QWEST CORPORATION (9636) | GOLDEN | 656 | — | — |
| 303-216 | A | Denver | Landline | QWEST CORPORATION (9636) | GOLDEN | 656 | — | — |
| 303-217 | 0 | Denver | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | DNVRCOMD4MD | 656 | — | — |
| 303-217 | 1 | Denver | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | DNVRCOMD4MD | 656 | — | — |
| 303-217 | 2 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-217 | 3 | Denver | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | DNVRCOMD4MD | 656 | — | — |
| 303-217 | 4 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-217 | 5 | Denver | Landline or VoIP | ONVOY, LLC - CO (026D) | DENVER | 656 | — | — |
| 303-217 | 6 | Denver | Wireless | T-MOBILE USA, INC. (6529) | DNVRCOII3MD | 656 | — | — |
| 303-217 | 7 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-217 | 8 | Denver | Landline or VoIP | ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM (3467) | DENVER | 656 | — | — |
| 303-217 | 9 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-217 | A | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-218 | 0 | Denver | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | DNVRCOMD4MD | 656 | — | — |
| 303-218 | 1 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-218 | 2 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-218 | 3 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-218 | 4 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-218 | 5 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-218 | 6 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-218 | 7 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-218 | 8 | Denver | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | DNVRCOMD4MD | 656 | — | — |
| 303-218 | 9 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-218 | A | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-219 | 0 | Denver | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - CO (078F) | DNVRCOMAXGZ | 656 | — | — |
| 303-219 | 1 | Denver | Landline or VoIP | ONVOY, LLC - CO (026D) | DENVER | 656 | — | — |
| 303-219 | 2 | Denver | Landline or VoIP | ONVOY, LLC - CO (026D) | DENVER | 656 | — | — |
| 303-219 | 3 | Denver | Landline or VoIP | ONVOY, LLC - CO (026D) | DENVER | 656 | — | — |
| 303-219 | 4 | Denver | Landline or VoIP | ONVOY, LLC - CO (026D) | DENVER | 656 | — | — |
| 303-219 | 5 | Denver | Landline or VoIP | ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM (3467) | DENVER | 656 | — | — |
| 303-219 | 6 | Denver | Landline or VoIP | ONVOY, LLC - CO (026D) | DENVER | 656 | — | — |
| 303-219 | 7 | Denver | Landline or VoIP | ONVOY, LLC - CO (026D) | DENVER | 656 | — | — |
| 303-219 | 8 | Denver | Landline or VoIP | ONVOY, LLC - CO (026D) | DENVER | 656 | — | — |
| 303-219 | 9 | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-219 | A | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-220 | A | Denver | Landline | QWEST CORPORATION (9636) | DRY CREEK | 656 | — | — |
| 303-221 | A | Denver | Landline | QWEST CORPORATION (9636) | DRY CREEK | 656 | — | — |
| 303-222 | A | Denver | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | DENVER | 656 | — | — |
| 303-223 | A | Denver | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CO (6118) | DENVER | 656 | — | — |
| 303-224 | A | Denver | Landline | QWEST CORPORATION (9636) | DRY CREEK | 656 | — | — |
| 303-225 | 0 | Denver | Landline or VoIP | ONVOY, LLC - CO (026D) | DENVER | 656 | — | — |
| 303-225 | 1 | Denver | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CO (6118) | DENVER | 656 | — | — |
| 303-225 | 2 | Denver | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CO (6118) | DENVER | 656 | — | — |
| 303-225 | 3 | Denver | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CO (6118) | DENVER | 656 | — | — |
| 303-225 | 4 | Denver | Landline or VoIP | ONVOY, LLC - CO (026D) | DENVER | 656 | — | — |
| 303-225 | 5 | Denver | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CO (6118) | DENVER | 656 | — | — |
| 303-225 | 6 | Denver | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CO (6118) | DENVER | 656 | — | — |
| 303-225 | 7 | Denver | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CO (6118) | DENVER | 656 | — | — |
| 303-225 | 8 | Denver | Landline or VoIP | ONVOY, LLC - CO (026D) | DENVER | 656 | — | — |
| 303-225 | 9 | Denver | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CO (6118) | DENVER | 656 | — | — |
| 303-225 | A | Denver | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CO (6118) | DENVER | 656 | — | — |
| 303-226 | A | Denver | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CO (6118) | DENVER | 656 | — | — |
| 303-227 | A | Denver | Landline | QWEST CORPORATION (9636) | DENVER NE | 656 | — | — |
| 303-228 | A | Denver | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - CO (6118) | DENVER | 656 | — | — |
| 303-229 | A | Denver | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CO (6567) | AURRCO20AMD | 656 | — | — |
| 303-230 | A | Denver | Landline or VoIP | SPOK, INC. (6630) | DNVRCOMAXTZ | 656 | — | — |
Block-level assignments from the North American Numbering Plan administrator, via localcallingguide.com.
Assigned Prefixes
785
Assignment Blocks
3,058
Rate Centers
13
Carriers of Record
39
| Type | Blocks | Share |
|---|---|---|
| Landline | 863 | 28% |
| Landline or VoIP | 1,249 | 41% |
| Wireless | 946 | 31% |
| Carrier | Blocks |
|---|---|
| QWEST CORPORATION | 855 |
| T-MOBILE USA, INC. | 375 |
| LEVEL 3 COMMUNICATIONS, LLC - CO | 325 |
| CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CO | 324 |
| ONVOY, LLC - CO | 231 |
| TELEPORT COMMUNICATIONS AMERICA, LLC - CO | 210 |
| NEW CINGULAR WIRELESS PCS, LLC | 188 |
| MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 185 |
| COMCAST IP PHONE, LLC | 112 |
| ONVOY SPECTRUM, LLC | 36 |
| 29 other carriers | 217 |
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 |
|---|---|---|
| Denver | 736 | 2,696 |
| Longmont | 18 | 98 |
| Fort Lupton | 11 | 101 |
| Deckers | 5 | 45 |
| Keenesburg | 3 | 33 |
| Allens Park-Lyons | 2 | 22 |
| Deer Trail | 2 | 5 |
| Georgetown | 2 | 22 |
| Hudson | 2 | 22 |
| Bennett | 1 | 1 |
| Byers | 1 | 1 |
| Roggen | 1 | 1 |
| Strasburg | 1 | 11 |
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 303 is a North American Numbering Plan (NANP) telephone area code assigned to Colorado, United States. It is one of 6 area codes serving Colorado. 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. 303 is an active North American Numbering Plan (NANP) area code, currently assigned to Colorado, United States. It is safe to answer or dial calls using this area code.
Area code 303 covers 13 cities and communities in Colorado, including Allens Park-Lyons, Bennett, Byers, Deckers, Deer Trail, and 8 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 303 area code observe Mountain Time (IANA timezone: America/Denver). Mountain Time is UTC−7 in winter (MST) and UTC−6 in summer (MDT). When placing a call to a 303 number from a different time zone, check the current local time above to avoid calling outside of business hours.
From within Colorado, dial the 7-digit local number directly if calling within the same rate center, or dial 1 + 303 + 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 1 303 XXX XXXX. The country code for both the United States and Canada in NANP is +1.
Format 303 numbers using E.164 notation as required by RFC 3966: prefix with +1 and omit dashes and parentheses (e.g., +13035550100). This format ensures tel: links work correctly on all mobile browsers and VoIP apps. See the tel: URI formatting guide for complete examples.