NumberingData
Verified Nov 1, 2026 · Source: NANPA CO Code Assignment Records

APTOS prefixes in area code 831

NANPA records 19 assigned NXX blocks to rate center APTOS in area code 831, 4.7% of the 406 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. 11 holders hold those blocks, the largest being PACIFIC BELL (7), ONVOY, LLC - CA (3), TELEPORT COMMUNICATIONS AMERICA, LLC - CA (1). The earliest assignment on record here is 2016-03-17 and the most recent 2023-08-11. 14 of them are in thousands-block pooling, so those prefixes are shared between carriers in 1,000-number lots.

19 assigned blocks – 4.7% of 831
11 holders of record
14 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
831-219 AT&T TELEPORT COMMUNICATIONS AMERICA, LLC - CA – yes yes
831-251 AT&T NEW CINGULAR WIRELESS PCS, LLC – no yes
831-257 Onvoy ONVOY, LLC - CA 2016-10-07 yes yes
831-280 COMMIO, LLC 2023-08-11 yes yes
831-318 Onvoy ONVOY, LLC - CA 2016-03-17 yes yes
831-531 Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC – yes yes
831-572 UTILITY TELECOM GROUP, LLC - CA – yes yes
831-603 Onvoy ONVOY, LLC - CA – no yes
831-607 IP HORIZON LLC – yes yes
831-612 Lumen LEVEL 3 COMMUNICATIONS, LLC - CA – yes yes
831-661 AT&T PACIFIC BELL – yes yes
831-662 AT&T PACIFIC BELL – no yes
831-684 AT&T PACIFIC BELL – yes yes
831-685 AT&T PACIFIC BELL – no yes
831-687 AT&T PACIFIC BELL – yes yes
831-688 AT&T PACIFIC BELL – no yes
831-689 AT&T PACIFIC BELL – yes yes
831-708 Bandwidth BANDWIDTH.COM CLEC, LLC - CA – yes yes
831-842 FRACTEL, LLC 2021-11-21 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

HolderBrandBlocksShare here
PACIFIC BELL AT&T 7 36.8%
ONVOY, LLC - CA Onvoy 3 15.8%
TELEPORT COMMUNICATIONS AMERICA, LLC - CA AT&T 1 5.3%
NEW CINGULAR WIRELESS PCS, LLC AT&T 1 5.3%
COMMIO, LLC – 1 5.3%
MCIMETRO ACCESS TRANSMISSION SERVICES LLC Verizon 1 5.3%
UTILITY TELECOM GROUP, LLC - CA – 1 5.3%
IP HORIZON LLC – 1 5.3%
LEVEL 3 COMMUNICATIONS, LLC - CA Lumen 1 5.3%
BANDWIDTH.COM CLEC, LLC - CA Bandwidth 1 5.3%
FRACTEL, LLC – 1 5.3%

Frequently asked

Which prefixes belong to APTOS in area code 831?

19 blocks: 219, 251, 257, 280, 318, 531, 572, 603, 607, 612, 661, 662 and 7 more, all listed in the table above.

Which carriers have numbers in APTOS?

PACIFIC BELL (7 blocks), ONVOY, LLC - CA (3 blocks), TELEPORT COMMUNICATIONS AMERICA, LLC - CA (1 block), NEW CINGULAR WIRELESS PCS, LLC (1 block), COMMIO, LLC (1 block), MCIMETRO ACCESS TRANSMISSION SERVICES LLC (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is APTOS 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.

Other rate centers in 831

All 406 prefixes in 831