Area code

CA

United States geographic area code, in service since 2024-11-01. Part of the 213/323/738 overlay complex — ten-digit dialing required.

Split from 323. Overlaid with 213, 323 .

Statusin service

Introduced2024-11-01

JurisdictionCA, US

Local dialing1+10D

Time zonePacific

Last verified2026-09-17

Utilization 5.1% of assignable prefixes assigned As of 09/17/2026

0%40 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 2025-09-08, most recent 2026-09-10.

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

Largest initial assignees in area code 738
Rank	Assignee	Prefixes	Share
01	ONVOY, LLC - CA	16	40%
02		14	35%
03	WIDE VOICE, LLC - CA	4	10%
04	T-MOBILE USA, INC.	2	5%
05	OPENTACT INC.	1	2.5%
06	EXIANT COMMUNICATIONS LLC	1	2.5%
07	BOOST SUBSCRIBERCO L.L.C.	1	2.5%
08	8X8, INC.	1	2.5%

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

2023-05-16 NPA 738 to Overlay NPA 213/323 (California) overlay
2024-11-01Area code 738 entered service (created from 323).

Planning letters & orders

Primary documents

NANPA planning letters for area code 738
Date	Document	Subject
2023-05-16	PL-614 ↗	NPA 738 to Overlay NPA 213/323 (California)

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