California · Pacific Time
628 Area Code
Area code 628 is in California, serving San Francisco and Marin County north of the Golden Gate. It is in the Pacific Time zone. It shares its territory with overlay code 415, so 10-digit dialing is required.
Last updated October 1, 2026 · Source: NANPA
Where is the 628 area code?
628 is a California area code covering San Francisco and Marin County north of the Golden Gate. In the wider directory it sits in the West region.
Cities in the 628 area code
- San Francisco
- San Rafael
- Novato
- Mill Valley
- Sausalito
- Larkspur
- Tiburon
- Corte Madera
- San Anselmo
- Fairfax
- Belvedere
Counties served by 628
San Francisco County and Marin County.
628 overlay codes and dialing
The 628 territory is covered by an overlay of 2 area codes: 415, 628. All of them serve the same geographic area, and the original code is 415. Because more than one code covers the same ground, 10-digit dialing is mandatory — you must dial the area code for every local call. New phone lines may be assigned any of these codes.
History of the 628 area code
628 went into service on March 21, 2015 as an overlay of 415, relieving number exhaustion in the San Francisco area. Rather than splitting the region, the overlay lets existing customers keep their numbers while new lines draw from the added code. Learn more in our overlay guide.
Is 628 a scam or spam risk?
628 is a legitimate geographic area code, not a premium or toll line, so a call from it costs you nothing extra. That said, scammers frequently spoof real local area codes to look familiar on caller ID. A genuine 628 number on your screen is no guarantee the caller is in San Francisco, CA or trustworthy. See spam & scam-risk area codes for how spoofing works and how to respond.
Other California area codes
Explore more
See every code in California, compare codes across the West region, or view all Pacific Time codes. You can also browse the 6XX block or the complete numeric list of US area codes.
New to how this all works? Start with how area codes work, then read up on overlays, 10-digit dialing, and spam & scam-risk codes. To check another number, use the area code lookup tool.
Quick answers
628 area code FAQ
Where is the 628 area code?
The 628 area code is in California, covering San Francisco and Marin County north of the Golden Gate, in the West region.
What cities are in the 628 area code?
Cities in the 628 area code include San Francisco, San Rafael, Novato, Mill Valley, Sausalito, Larkspur, Tiburon, Corte Madera, San Anselmo and Fairfax.
What time zone is 628 in?
628 is in the Pacific Time zone.
What is the overlay for the 628 area code?
628 shares its territory with 415. Both codes (415, 628) serve the same area, so 10-digit dialing is required for every call.
When did the 628 area code start?
628 went into service on March 21, 2015 as an overlay of 415.
Do I have to dial 10 digits for 628?
Yes. Because 628 is an overlay area, you must dial the full 10-digit number (area code + 7 digits) for every call.
Is 628 a toll-free or premium code?
No. 628 is a standard geographic area code, so calling it costs the same as any local or long-distance call on your plan. Toll-free calls use 800, 888, 877, 866, 855, 844 or 833.