Area code 858 – California
858 has served California since 1999, split from 619. 564 of its 786 number blocks are allocated (72%). AT&T is the largest holder with 41.7% of blocks, ahead of Other CLEC / VoIP at 20.2%. It shares its geography with overlay codes 619, so local calls take all ten digits. FTC complaints naming a 858 caller ID totalled 620 in the 33 days to 30 October 2026 (166th of 422 ranked codes).
- State
- California
- In service since
- 1999
- Time zone
- Pacific
- Shares area with
- 619
Who holds 858 number blocks
Share of the 564 assigned NXX blocks (71.8% of the 786 possible), across 40 carriers. This is share of number blocks, not of subscribers.
- AT&T41.7%
- Other CLEC / VoIP13.3%
- Verizon11.3%
- T-Mobile8%
- Lumen6.7%
- Onvoy6.2%
- TPx4.3%
- Comcast2.7%
- Windstream1.4%
- Bandwidth1.4%
- Charter0.9%
- American Messaging0.7%
- Vonage0.4%
- Spok0.4%
- Peerless0.2%
- Telnyx0.2%
- Twilio0.2%
- 8x80.2%
Spam complaints naming 858
FTC Do Not Call complaints where the caller ID was a 858 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 858
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 19.
Timeline
- 1999 858 goes into service, split from or overlaid on 619.
More about 858
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 858
What state is area code 858?
California. It covers the same area as 619/858.
Is a call from 858 a scam?
Not by itself. 858 drew 620 FTC complaints in the 33 days to 30 October 2026, 166th 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 858 numbers?
AT&T holds the largest share of assigned number blocks at 41.7%. 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 858?
NANPA records the local dialing plan for 858 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.