Area codes in San Leandro, California
San Leandro, California uses 2 area codes — 510 and 341. The main San Leandro area code is 510.
Area codes serving San Leandro
Phone numbers in San Leandro are written as ten digits — for example (510) 555-0190 — and fall in the Pacific Time zone.
How San Leandro came to have 2 area codes
The original San Leandro area code is 510, in service since 1991. As the area ran low on available numbers, an overlay code was added over the same region for new phone lines: 341 (2019). Existing numbers kept their original code — an overlay never forces anyone to change their number — which is why San Leandro now uses all 2 codes and every local call is dialed with ten digits.
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More cities in California
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Frequently asked questions
What is the area code for San Leandro?
The main area code for San Leandro, California is 510. San Leandro is now served by 2 area codes in total: 510, 341.
How many area codes does San Leandro have?
San Leandro has 2 area codes: 510, 341.
Why does San Leandro have more than one area code?
As San Leandro used up the numbers available in its original area code (510, in service since 1991), additional "overlay" codes were added over the same area so new phone numbers could keep being assigned.
How do you dial a San Leandro number?
Dial all 10 digits — the area code (510 or 341) followed by the 7-digit local number. From abroad, dial +1, then the area code and number.
Sourced from the official NANPA (North American Numbering Plan Administrator) numbering database, current as of August 2, 2026. Refreshed monthly.