San Francisco (overlay)

Area code 628 is an all-services overlay of area code 415, serving the same territory of San Francisco, Marin County, and a small part of San Mateo County. It went into service in 2015.

The essentials Numbering data · NumberResearch · as of 2026-09-18

Place

Type

geographic

Status

in service

In service since

2015

Projected exhaust

2072 Q4

Status, dates and counts are read from NumberResearch (NANPA / CNAC / FCC records). Assignment records show initial assignees, not the carrier serving a number today.

A · Where it is

Where 628 is

Same as 415: San Francisco, Marin County, and northeastern San Mateo County..

Communities served wholly or partly by 628:

San FranciscoSan RafaelNovatoMill ValleySausalitoDaly City

Shares the 415 service area.

B · Relationships

How it relates to other codes

The codes 628 was split from, spawned, or shares its area with. A split divides the map and changes some numbers; an overlay shares the same ground and changes none — what's the difference?

Overlay · 2015 415 San Francisco All-services overlay of the original 415 numbering plan area.

What's changing. Active overlay of 415; ten-digit dialing required.

C · History

How 628 got here

2015-02-21

Area code 628 added as an overlay on 415; mandatory ten-digit dialing began.

Source: Wikipedia

D · Capacity

How full it is

Prefixes assigned

208

Prefixes available

592

Thousands-blocks assigned

1,865

Prefix-assignment counts describe allocation to carriers, not how many individual numbers are in use. Full technical records: NumberResearch ↗.

Compare 628 with another code →

Sources

Wikipedia ↗

Area codes 415 and 628

NumberResearch.org ↗

Live status, dates, assignment counts and exhaust forecast — data as of 2026-09-18 (CC BY 4.0).

Place, relationships and history above are compiled by North American Numbers from the sources listed and last checked 2026-09-18. A check date is not an expert review — see how this is made. Flag an error.