North American Numbers Source-cited · ownership disclosed
Area code
831
In service
United States · since 1998

Monterey / Salinas

Area code 831 serves the Central Coast of California, covering Monterey, Santa Cruz, and San Benito Counties. It was split from 408 in 1998 and has no overlay.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
Monterey / Salinas
Type
geographic
Status
in service
In service since
1998
Projected exhaust
2078 Q2

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 831 is

Monterey County, Santa Cruz County, and San Benito County (Central Coast)..

Communities served wholly or partly by 831:

SalinasMontereySanta CruzHollisterWatsonvilleCarmel-by-the-SeaPacific Grove

Representative list; the three counties include dozens of additional communities.

B · Relationships

How it relates to other codes

The codes 831 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?

Split from · 1998 408 San Jose Split from 408 on July 11, 1998; permissive dialing ended February 20, 1999.
Related 650 San Mateo / Palo Alto Adjacent to the north.
Related 805 Santa Barbara / Ventura / San Luis Obispo Adjacent to the south (805/820).
What's changing. No overlay; standalone area code, exhaustion considered unlikely for the foreseeable future.
C · History

How 831 got here

1998-07-11
Area code 831 created via geographic split from 408; permissive dialing ended February 20, 1999.
Source: Wikipedia
D · Capacity

How full it is

Prefixes assigned
442
Prefixes available
358
Thousands-blocks assigned
2,068

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

Compare 831 with another code →
Sources
Wikipedia ↗
Area code 831
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.