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Area code 510

Area code 510 serves California, including Oakland, Hayward and Fremont-Newark (Pacific time). It has been in service since September 2, 1991 and shares its area with 341.

Numbers starting with 510 drew 1,828 reports to the FTC from Aug 14, 2026 to Nov 11, 2026 and 582 complaints to the FCC since November 2023. The number on your screen can be faked, so a 510 number proves nothing about where a call came from.

Location
CaliforniaSan Francisco-Oakland-Fremont, CA Metropolitan Statistical Area
Time zone
Pacific
In service since
September 2, 1991Created from 415
Overlay
Same area as 341
Local calls
Dial 1 + 10 digits
Exchanges in use
785 of 792held by 32 carriers
Projected to run out
2Q 2085NANPA forecast 2026.2

Complaints about 510 numbers

Reports where the number on the consumer's caller ID (or, for the FCC, the number the caller asked them to call back) starts with 510. These are counts of what people reported; the agencies do not verify them.

FTC reports, Aug 14, 2026 to Nov 11, 2026

1,828

FCC complaints since November 2023

582

Different 510 numbers reported

2,194

FCC complaints naming a 510 number, by month

November 2023 to October 2026. Source: FCC Consumer Complaints Data.

Show as a table
MonthComplaints
November 202311
December 202312
January 202413
February 20247
March 202411
April 202412
May 202420
June 20247
July 202416
August 202413
September 202414
October 202424
November 202417
December 20248
January 202522
February 202517
March 202524
April 202526
May 202517
June 202514
July 202517
August 202527
September 202514
October 20250
November 20258
December 20255
January 20267
February 20269
March 202617
April 20268
May 202615
June 202622
July 202620
August 202619
September 202623
October 202636

What people said 510 calls were about

Subjects picked in FTC reports, August 14, 2026 to November 11, 2026. 937 of 1,828 reports were robocalls.

Show as a table
SubjectReports
Other879
Dropped call or no message252
Reducing your debt (credit cards, mortgage, student loans)181
Calls pretending to be government, businesses, or family and friends174
Energy, solar, and utilities82
Medical and prescriptions51

Most reported 510 numbers

Numbers with at least five reports from three or more places in the last twelve months. Many of them are likely spoofed.

Places served by 510

NANPA lists 13 rate centers for 510. A rate center is the town or district a block of numbers is tied to for billing; sorted here by how many exchanges each holds.
  • Oakland: Main-Piedmont DA204
  • Hayward117
  • Fremont-Newark: Main DA81
  • Oakland: Berkeley DA70
  • Oakland: Trinidad DA60
  • Richmond53
  • Fremont-Newark: Oliver DA45
  • Oakland: Alameda DA42
  • Oakland: Fruitvale DA39
  • El Sobrante-Pinole28
  • Fremont-Newark: Greenleaf DA25
  • Hercules-Rodeo14
  • Crockett7

Phone companies holding 510 exchanges

Each exchange (the three digits after the area code) is assigned to one carrier. 65% of these exchanges are pooled: their numbers are handed out in blocks of 1,000 to other carriers, so the holder below is not always the company serving a given number.

Exchanges held, top 8 of 32 carriers

NANPA central office code assignments, file of November 11, 2026.

Show as a table
Carrier (legal name)Exchanges
Pacific Bell277
New Cingular Wireless PCS, LLC78
T-Mobile USA, Inc.65
Cellco Partnership dba Verizon Wireless - CA60
Metropcs, Inc.45
Mcimetro Access Transmission Services LLC37
Onvoy, LLC - CA37
Level 3 Communications, LLC - CA34

When today's 510 exchanges were assigned

Exchanges still assigned, by year of assignment. Exchanges returned since are not counted.

Show as a table
YearExchanges
200126
20027
20041
20061
20075
20085
20093
20106
20118
20127
201311
201420
201521
201621
20176
201812
201913
20203
20214
20233
20247
20261

Check a 510 number

A check shows the carrier and rate center of the number's exchange and every FTC and FCC report about that exact number. Why the number on screen can be fake.

Other area codes in California

NANPA area code database and central office code file of November 11, 2026; FCC complaints November 1, 2023 to November 11, 2026; FTC reports August 14, 2026 to November 11, 2026. How the data is used.

Official sources (7)Show