323
Area code
CA
United States geographic area code, in service since 1998-06-13. Part of the 213/323/738 overlay complex — ten-digit dialing required.
Statusin service
Introduced1998-06-13
JurisdictionCA, US
Local dialing1+10D
Time zonePacific
Last verified2026-09-17
Utilization 101% of assignable prefixes assigned
As of 09/17/2026
0%800 of ~792 assignable NXX values (200–999 excl. N11)100%
Prefix-level assignment does not equal number-level exhaustion; thousands-block pooling extends capacity. First assignment on record 2001-01-23, most recent 2025-04-02.
Area codes serve rate-center geographies, not municipal boundaries. “CA” identifies the jurisdiction, not an exact city footprint.
Top assignees
Ranked by assigned prefixes · initial assignee ≠ current carrier| Rank | Assignee | Prefixes | Share |
|---|---|---|---|
| 01 | PACIFIC BELL | 265 | 33.1% |
| 02 | METROPCS NETWORKS, LLC | 85 | 10.6% |
| 03 | T-MOBILE USA, INC. | 64 | 8% |
| 04 | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | 45 | 5.6% |
| 05 | NEW CINGULAR WIRELESS PCS, LLC | 39 | 4.9% |
| 06 | BANDWIDTH.COM CLEC, LLC - CA | 38 | 4.8% |
| 07 | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 37 | 4.6% |
| 08 | LEVEL 3 COMMUNICATIONS, LLC - CA | 34 | 4.3% |
| 09 | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 29 | 3.6% |
| 10 | ONVOY, LLC - CA | 25 | 3.1% |
Important: these are initial assignees from NANPA CO-code records — the carrier a prefix was originally assigned to. Because of number portability, the current serving carrier of any individual number may differ.
Change history
Recorded events for this NPA- 1998-06-13Area code 323 entered service (created from 213).
Planning letters & orders
Primary documents| Date | Document | Subject |
|---|---|---|
| 2023-05-16 | PL-614 ↗ | NPA 738 to Overlay NPA 213/323 (California) |
| 2016-08-09 | PL-494 ↗ | NPA 213 and 323 Boundary Elimination Overlay (California) |
| 1997-08-13 | PL-080 ↗ | Changes in Test Numbers and Effective Dates for California NPA Splits |
| 1997-05-19 | PL-062 ↗ | NANP- Split of 213 (California) Numbering Plan Area (NPA) |