The 341 area code covers the same area as 510, including Oakland, Hayward and 3 more places in California.
Area code 341 is in California, on Pacific Time. In the 341 area, phone numbers are given out most in Alameda County, then Contra Costa County. It has been in service since July 22, 2019. 510 covers the same area, so two neighbours can have different area codes.
- Where
- Alameda County and Contra Costa County, California
- Time zone
- Pacific Time
- In service since
- July 22, 2019
- Shares its area with
- 510 (since 1991)
- Prefixes in use
- 113
- How to dial
- Local calls need 1, then the area code, then the number: 1-341-555-0142.
Find out who called you from a 341 number.
Enter the full 10-digit number to see who it is listed to and the city and state on the listing. It is the same free check as our who called me lookup. To see only the caller ID name on the number, use our free CNAM lookup. To see whether it is a mobile, a landline or a VoIP line, use our free VoIP checker. To see which carrier a (341) number is on today, use our free carrier lookup.
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Oakland holds 38% of the phone prefixes in area code 341.
A prefix is the three digits after the area code, and NANPA assigns each one to a town. Counting the 113 prefixes in use shows where 341 numbers are actually given out.
- Oakland43 prefixes, 38%
- Hayward13 prefixes, 12%
- Richmond10 prefixes, 9%
- Hercules3 prefixes, 3%
- Crockett3 prefixes, 3%
Fractel holds the most phone number prefixes in area code 341: 33 of 113.
NANPA, which runs the North American numbering plan, assigns each prefix (the three digits after the area code) to one carrier. Here is how the 113 prefixes in use in 341 divide between carriers; holders this page does not name are grouped as other carriers.
| Carrier | Prefixes | Share |
|---|---|---|
| Fractel | 33 | 29% |
| AT&T MobilityMobile network | 12 | 11% |
| T-MobileMobile network | 12 | 11% |
| BandwidthSupplies numbers to VoIP and app-based phone services | 8 | 7% |
| Sonic Telecom | 4 | 4% |
| Teleport (AT&T)AT&T's business phone network | 2 | 2% |
| 9 other carriers | 42 | 37% |
99% of these prefixes are pooled, which means the blocks of 1,000 numbers inside them can belong to other carriers. Any number can also have been moved to another carrier since, so this shows who holds the prefixes, not who serves a given number.
Want the carrier of one exact number? Our free carrier lookup checks it, because numbers move between carriers.
Source: NANPA central office code assignments, October 1, 2026.
341 started in 2019 as an overlay on 510, and its ground has not changed since.
2019
341 starts on July 22, 2019, as an overlay on 510: new numbers on the same ground.
A 341 number on your screen can still be a scam, because caller ID is easy to fake.
- Let an unknown call go to voicemail. A real caller leaves a message; a robocaller usually does not.
- Look the number up with the box above before you call back, because calling back tells a robocaller your line is live.
- Hang up on anyone who wants gift cards, crypto or a wire transfer, or asks you to read out a code that was just texted to you.
- Report unwanted robocalls at reportfraud.ftc.gov, or paste a suspicious message into our free scam checker.
The area codes closest to 341 are 925, 650 and 415.
This list measures the distance between the centres of each area, across state lines, and shows codes that share one area together.
California has 40 other area codes.
These are the questions people ask most about area code 341.
Where is area code 341?
341 covers Oakland, Hayward, Richmond and Hercules and 1 more places in California. In the 341 area, phone numbers are given out most in Alameda County, then Contra Costa County.
What state is area code 341 in?
California. 341 is a California area code on Pacific Time.
What cities use area code 341?
The places holding the most 341 prefixes are Oakland, Hayward, Richmond, Hercules and Crockett. The count comes from NANPA's prefix assignments as of October 1, 2026.
Which phone company owns area code 341?
No single phone company owns 341. NANPA's records show Fractel holds the most 341 prefixes, 33 of 113, followed by AT&T Mobility and T-Mobile. Numbers move between carriers, so check one exact number with a carrier lookup.
What time zone is area code 341 in?
341 is on Pacific Time.
When did area code 341 start?
341 went into service on July 22, 2019, as an overlay on 510: new numbers for the same area.
Is 341 the same area as 510?
Yes. 510 (since 1991) covers the same ground as 341. Nobody's number changed when it was added; new lines simply get whichever code has numbers left, so two neighbours can have different codes.
How do I dial a 341 number?
Local calls need 1, then the area code, then the number: 1-341-555-0142.
Is 341 a toll-free number?
No. 341 is a regular area code for Oakland and Hayward in California, not a toll-free one. The toll-free codes in North America are 800, 833, 844, 855, 866, 877 and 888.
What area codes are near 341?
The closest are 925 (Walnut Creek, California), 650 (Palo Alto, California), 415/628 (San Francisco, California) and 408/669 (San Jose, California), measured between the centres of each area.
Who called me from a 341 number?
Enter the full 10-digit number in the lookup above. It returns the listed owner where there is a public record, where the number is registered, and whether it is a mobile, a landline or a VoIP line.
Is area code 341 a scam?
341 is a real California area code, so the code itself is not a warning sign. Scam callers fake local-looking numbers on purpose, so judge the call by what the caller asks for, and look the number up before calling back.
Put this lookup on your site: our free area code widget takes two lines of code and shows any US area code's state, time zone and local time.
Source: NANPA, the North American Numbering Plan Administrator: its area code database and prefix assignments, as of October 1, 2026.