Area code 424 – California
424 has served California since 2006, split from 310. 460 of its 786 number blocks are allocated (59%). No carrier dominates: T-Mobile 16.1%, Onvoy / Inteliquent 15.0%, AT&T 13.9%. It shares its geography with overlay codes 310, so local calls take all ten digits. FTC complaints naming a 424 caller ID totalled 631 in the 33 days to 30 October 2026 (163rd of 422 ranked codes).
- State
- California
- In service since
- 2006
- Time zone
- Pacific
- Shares area with
- 310
Who holds 424 number blocks
Share of the 460 assigned NXX blocks (58.5% of the 786 possible), across 27 carriers. This is share of number blocks, not of subscribers.
- T-Mobile21.1%
- Onvoy15%
- AT&T13.9%
- Verizon10.9%
- Lumen10%
- Bandwidth9.8%
- Other CLEC / VoIP8.7%
- Charter4.8%
- Peerless1.7%
- Windstream1.5%
- TPx1.3%
- Comcast0.7%
- Frontier0.2%
- Telnyx0.2%
- VoIP Innovations0.2%
Spam complaints naming 424
FTC Do Not Call complaints where the caller ID was a 424 number, 28 Sep – 30 Oct 2026 (33 days). Caller IDs on spam calls are frequently spoofed, so these are complaints about the code, not calls proven to originate in it.
Rate centers in 424
NANPA allocates number blocks to rate centers and records their names abbreviated to ten characters, so these are NANPA's codes rather than place names – CHAMPAURBN is Champaign-Urbana, NWYRCYZN01 is a New York City zone. We show them unchanged instead of guessing at the full names. Showing the largest 5 of 16.
Timeline
- 2006 424 goes into service, split from or overlaid on 310.
More about 424
Separate pages for the questions that need their own answer: what time it is there, what the complaint data says, who holds the number blocks, and how the code compares with the one it shares its area with.
Frequently asked about 424
What state is area code 424?
California. It covers the same area as 310/424.
Is a call from 424 a scam?
Not by itself. 424 drew 631 FTC complaints in the 33 days to 30 October 2026, 163rd of 422 ranked codes – mid-pack or lower. Spam callers spoof caller IDs, so the only useful check is the full number.
Which carrier owns 424 numbers?
T-Mobile holds the largest share of assigned number blocks at 16.1%. The rest is spread across 3 other carriers. This is share of number blocks, not of subscribers – people keep their numbers when they switch carriers.
Do I need to dial 10 digits in 424?
NANPA records the local dialing plan for 424 as “1+10D”.
Sources and verification
- NANPA – NPA Database (npa_report.csv), file date 11/01/2026, retrieved Nov 1, 2026
- NANPA – CO Code Assignment Records, All States (utilized), file updated 11/01/2026, retrieved Nov 1, 2026
- FTC – Do Not Call Reported Calls Data, 25 daily files 28 Sep – 30 Oct 2026, retrieved Nov 1, 2026
NANPA dialing note for this code: “1+10D”. Reviewed by the data desk. Spotted an error? Request a correction.