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

ATWATER prefixes in area code 350

NANPA records 7 assigned NXX blocks to rate center ATWATER in area code 350, 8.0% of the 88 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. 4 holders hold those blocks, the largest being T-MOBILE USA, INC. (3), NEW CINGULAR WIRELESS PCS, LLC (2), ONVOY, LLC - CA (1). The earliest assignment on record here is 2023-01-11 and the most recent 2026-06-30. 7 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 209, 234, 320, 330 – overlay codes cover the same geography, so a rate center is served by all of them.

7 assigned blocks – 8% of 350
4 holders of record
7 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
350-204 T-Mobile T-MOBILE USA, INC. 2023-01-11 yes yes
350-224 AT&T NEW CINGULAR WIRELESS PCS, LLC 2024-05-29 yes yes
350-233 T-Mobile T-MOBILE USA, INC. 2024-10-21 yes yes
350-248 T-Mobile T-MOBILE USA, INC. 2025-08-20 yes yes
350-249 AT&T NEW CINGULAR WIRELESS PCS, LLC 2025-08-22 yes yes
350-258 Onvoy ONVOY, LLC - CA 2026-06-30 yes yes
350-500 Charter ONVOY SPECTRUM, LLC 2023-11-14 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
T-MOBILE USA, INC. T-Mobile 3 42.9%
NEW CINGULAR WIRELESS PCS, LLC AT&T 2 28.6%
ONVOY, LLC - CA Onvoy 1 14.3%
ONVOY SPECTRUM, LLC Charter 1 14.3%

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 ATWATER in area code 350?

7 blocks: 204, 224, 233, 248, 249, 258, 500. The table above gives the holder of each.

Which carriers have numbers in ATWATER?

T-MOBILE USA, INC. (3 blocks), NEW CINGULAR WIRELESS PCS, LLC (2 blocks), ONVOY, LLC - CA (1 block), ONVOY SPECTRUM, 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 ATWATER 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 350

All 88 prefixes in 350