Verified Nov 1, 2026 · Source: NANPA CO Code Assignment Records
CMTN GRDN prefixes in area code 310
NANPA records 124 assigned NXX blocks to rate center CMTN GRDN in area code 310, 15.8% of the 786 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. 16 holders hold those blocks, the largest being PACIFIC BELL (31), NEW CINGULAR WIRELESS PCS, LLC (24), CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA (23). The earliest assignment on record here is 2001-04-17 and the most recent 2012-08-14. 45 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 213, 424, 562 – overlay codes cover the same geography, so a rate center is served by all of them.
124 assigned blocks – 15.8% of 310
16 holders of record
45 of them pooled in 1,000-number lots
Prefixes assigned here
| Prefix | Holder of record | Assigned | Pooled | In service |
|---|---|---|---|---|
| 310-200 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-04-19 | no | yes |
| 310-213 | T-Mobile T-MOBILE USA, INC. | – | yes | yes |
| 310-217 | AT&T PACIFIC BELL | – | no | yes |
| 310-225 | AT&T PACIFIC BELL | – | yes | yes |
| 310-240 | Spok SPOK, INC. | – | no | yes |
| 310-243 | AT&T PACIFIC BELL | – | yes | yes |
| 310-245 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-04-19 | no | yes |
| 310-249 | Spok SPOK, INC. | – | no | yes |
| 310-250 | Spok SPOK, INC. | – | no | yes |
| 310-251 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-04-19 | no | yes |
| 310-283 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-04-19 | no | yes |
| 310-291 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-04-19 | no | yes |
| 310-292 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-04-19 | no | yes |
| 310-293 | AT&T NEW CINGULAR WIRELESS PCS, LLC | – | no | yes |
| 310-296 | American Messaging AMERICAN MESSAGING SERVICES, LLC | – | no | yes |
| 310-298 | Spok SPOK, INC. | – | no | yes |
| 310-308 | AT&T NEW CINGULAR WIRELESS PCS, LLC | – | no | yes |
| 310-323 | AT&T PACIFIC BELL | – | no | yes |
| 310-324 | AT&T PACIFIC BELL | – | no | yes |
| 310-327 | AT&T PACIFIC BELL | – | no | yes |
| 310-329 | AT&T PACIFIC BELL | – | no | yes |
| 310-344 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-04-19 | no | yes |
| 310-345 | T-Mobile T-MOBILE USA, INC. | – | yes | yes |
| 310-346 | T-Mobile T-MOBILE USA, INC. | – | yes | yes |
| 310-352 | AT&T PACIFIC BELL | – | yes | yes |
| 310-353 | AT&T PACIFIC BELL | – | yes | yes |
| 310-354 | AT&T PACIFIC BELL | – | no | yes |
| 310-365 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-366 | AT&T PACIFIC BELL | – | no | yes |
| 310-368 | Spok SPOK, INC. | – | no | yes |
| 310-380 | AT&T PACIFIC BELL | – | yes | yes |
| 310-386 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-387 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-389 | American Messaging AMERICAN MESSAGING SERVICES, LLC | – | no | yes |
| 310-400 | T-Mobile T-MOBILE USA, INC. | – | yes | yes |
| 310-404 | T-Mobile T-MOBILE USA, INC. | – | yes | yes |
| 310-413 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-415 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-418 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-04-19 | no | yes |
| 310-436 | TPx U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | – | yes | yes |
| 310-464 | Lumen LEVEL 3 COMMUNICATIONS, LLC - CA | – | yes | yes |
| 310-480 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-04-19 | no | yes |
| 310-489 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-04-19 | no | yes |
| 310-493 | T-Mobile T-MOBILE USA, INC. | – | yes | yes |
| 310-502 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-503 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-04-19 | no | yes |
| 310-505 | T-Mobile T-MOBILE USA, INC. | – | yes | yes |
| 310-508 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-512 | AT&T PACIFIC BELL | – | no | yes |
| 310-515 | AT&T PACIFIC BELL | – | no | yes |
| 310-516 | AT&T PACIFIC BELL | – | no | yes |
| 310-523 | AT&T PACIFIC BELL | – | no | yes |
| 310-525 | AT&T TELEPORT COMMUNICATIONS AMERICA, LLC - CA | – | yes | yes |
| 310-527 | AT&T PACIFIC BELL | – | yes | yes |
| 310-528 | AT&T NEW CINGULAR WIRELESS PCS, LLC | – | no | yes |
| 310-532 | AT&T PACIFIC BELL | – | no | yes |
| 310-538 | AT&T PACIFIC BELL | – | no | yes |
| 310-567 | AT&T NEW CINGULAR WIRELESS PCS, LLC | – | no | yes |
| 310-594 | T-Mobile T-MOBILE USA, INC. | – | yes | yes |
| 310-610 | American Messaging AMERICAN MESSAGING SERVICES, LLC | – | no | yes |
| 310-612 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-613 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-617 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-630 | AT&T PACIFIC BELL | – | yes | yes |
| 310-650 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-660 | AT&T PACIFIC BELL | – | yes | yes |
| 310-678 | T-Mobile T-MOBILE USA, INC. | – | yes | yes |
| 310-681 | American Messaging AMERICAN MESSAGING SERVICES, LLC | – | no | yes |
| 310-685 | Spok SPOK, INC. | – | no | yes |
| 310-701 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-702 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-704 | T-Mobile T-MOBILE USA, INC. | – | yes | yes |
| 310-710 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-713 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-714 | T-Mobile T-MOBILE USA, INC. | – | yes | yes |
| 310-715 | AT&T PACIFIC BELL | – | yes | yes |
| 310-716 | Spok SPOK, INC. | – | no | yes |
| 310-718 | Spok SPOK, INC. | – | no | yes |
| 310-719 | AT&T PACIFIC BELL | – | yes | yes |
| 310-720 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-722 | T-Mobile T-MOBILE USA, INC. | – | yes | yes |
| 310-723 | Spok SPOK, INC. | – | no | yes |
| 310-738 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-748 | AT&T NEW CINGULAR WIRELESS PCS, LLC | – | no | yes |
| 310-749 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-753 | AT&T NEW CINGULAR WIRELESS PCS, LLC | – | no | yes |
| 310-756 | Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC | – | yes | yes |
| 310-766 | T-Mobile METROPCS NETWORKS, LLC | – | yes | yes |
| 310-767 | AT&T PACIFIC BELL | – | yes | yes |
| 310-768 | AT&T PACIFIC BELL | – | yes | yes |
| 310-769 | AT&T PACIFIC BELL | – | yes | yes |
| 310-771 | AT&T PACIFIC BELL | – | no | yes |
| 310-778 | UTILITY TELECOM GROUP, LLC - CA | – | yes | yes |
| 310-780 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-800 | Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA | – | yes | yes |
| 310-805 | Spok SPOK, INC. | – | no | yes |
| 310-807 | Onvoy ONVOY, LLC - CA | – | yes | yes |
| 310-808 | AT&T PACIFIC BELL | – | yes | yes |
| 310-817 | AT&T PACIFIC BELL | – | yes | yes |
| 310-818 | TPx U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | – | yes | yes |
| 310-819 | Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA | – | yes | yes |
| 310-850 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-851 | AT&T PACIFIC BELL | – | no | yes |
| 310-852 | American Messaging AMERICAN MESSAGING SERVICES, LLC | – | no | yes |
| 310-856 | TPx U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | – | yes | yes |
| 310-864 | T-Mobile METROPCS NETWORKS, LLC | – | yes | yes |
| 310-874 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-04-19 | no | yes |
| 310-878 | Lumen LEVEL 3 COMMUNICATIONS, LLC - CA | – | yes | yes |
| 310-879 | Bandwidth BANDWIDTH.COM CLEC, LLC - CA | 2012-08-14 | yes | yes |
| 310-892 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | yes | yes |
| 310-897 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-04-17 | no | yes |
| 310-918 | AT&T NEW CINGULAR WIRELESS PCS, LLC | – | no | yes |
| 310-920 | T-Mobile T-MOBILE USA, INC. | 2001-10-18 | no | yes |
| 310-930 | T-Mobile METROPCS NETWORKS, LLC | 2001-06-26 | yes | yes |
| 310-940 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-08-22 | no | yes |
| 310-941 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-07-10 | no | yes |
| 310-942 | 33 WIRELESS INC. | 2002-04-15 | no | yes |
| 310-960 | Spok SPOK, INC. | – | no | yes |
| 310-965 | AT&T PACIFIC BELL | – | yes | yes |
| 310-977 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2001-04-19 | no | yes |
| 310-989 | AT&T NEW CINGULAR WIRELESS PCS, LLC | – | no | yes |
| 310-991 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-995 | Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | – | no | yes |
| 310-999 | T-Mobile T-MOBILE USA, INC. | – | 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 |
|---|---|---|---|
| PACIFIC BELL | AT&T | 31 | 25% |
| NEW CINGULAR WIRELESS PCS, LLC | AT&T | 24 | 19.4% |
| CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | Verizon | 23 | 18.5% |
| T-MOBILE USA, INC. | T-Mobile | 14 | 11.3% |
| SPOK, INC. | Spok | 11 | 8.9% |
| AMERICAN MESSAGING SERVICES, LLC | American Messaging | 5 | 4% |
| U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | TPx | 3 | 2.4% |
| METROPCS NETWORKS, LLC | T-Mobile | 3 | 2.4% |
| LEVEL 3 COMMUNICATIONS, LLC - CA | Lumen | 2 | 1.6% |
| MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA | Verizon | 2 | 1.6% |
| TELEPORT COMMUNICATIONS AMERICA, LLC - CA | AT&T | 1 | 0.8% |
| MCIMETRO ACCESS TRANSMISSION SERVICES LLC | Verizon | 1 | 0.8% |
| UTILITY TELECOM GROUP, LLC - CA | – | 1 | 0.8% |
| ONVOY, LLC - CA | Onvoy | 1 | 0.8% |
| BANDWIDTH.COM CLEC, LLC - CA | Bandwidth | 1 | 0.8% |
| 33 WIRELESS INC. | – | 1 | 0.8% |
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 CMTN GRDN in area code 310?
124 blocks: 200, 213, 217, 225, 240, 243, 245, 249, 250, 251, 283, 291 and 112 more, all listed in the table above.
Which carriers have numbers in CMTN GRDN?
PACIFIC BELL (31 blocks), NEW CINGULAR WIRELESS PCS, LLC (24 blocks), CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA (23 blocks), T-MOBILE USA, INC. (14 blocks), SPOK, INC. (11 blocks), AMERICAN MESSAGING SERVICES, LLC (5 blocks). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.
Is CMTN GRDN 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.