---
title: "Area code 310: California, United States"
url: "https://lookvalid.com/area-code/310.md"
canonical_url: "https://lookvalid.com/area-code/310"
last_updated: "2026-10-23"
type: "reference"
summary: "Area code 310 serves California, United States. Number formats, numbering rules, a live phone validator and the other codes in California."
---

# Area code 310: California, United States

Area code 310 serves California, United States. Number formats, numbering rules, a live phone validator and the other codes in California.

NANPA lists 786 central office codes (prefixes) in use in area code 310, held by 24 holders across 17 rate centers.
Pacific Bell holds the most prefixes, 249 (32%). 45% of the prefixes are pooled, which means their thousands-blocks can belong to different companies.
The FCC unwanted-call data has 5,504 complaints on file for 3,708 numbers in 310, most often filed as "Unwanted Calls". These are consumer reports, not findings.

## Facts

- In service since: 1991-11-02
- Time zone: Pacific (P)
- Assigned overlays: 424 (2006-08-26)
- Prefixes in use: 786
- Pooled prefixes: 354 (45%)
- Rate centers: 17
- Companies holding prefixes: 24
- Assignment dates on file: 2001-02-28 to 2025-11-20 (101 prefixes)
- ZIP codes in its places: 43

## Rate centers

| Rate center | Prefixes | Share |
| --- | --- | --- |
| CMTN GRDN | 124 | 16% |
| BEVERLYHLS | 113 | 14% |
| SNMN SNMN | 84 | 11% |
| W ANGELES | 69 | 9% |
| SNMN MRVS | 54 | 7% |
| INGLEWOOD | 49 | 6% |
| CMTN CMTN | 44 | 6% |
| REDONDO | 44 | 6% |
| 9 other rate centers | 205 | 26% |

## Carriers

| Holder | Prefixes | Share |
| --- | --- | --- |
| Pacific Bell | 249 | 32% |
| Frontier California | 137 | 17% |
| New Cingular Wireless PCS | 68 | 9% |
| T-Mobile USA | 58 | 7% |
| Verizon Wireless | 56 | 7% |
| Mcimetro Access Transmission Services | 46 | 6% |
| 18 other carriers | 172 | 22% |

A prefix holder is the company a code was assigned to, not necessarily a number's current carrier, because numbers can be ported to another company.

## History

- 1947-01-01: Area code 213, named as the parent of 310 in the NANPA report, was in service.
- 1991-11-02: Area code 310 went into service.
- 1997-01-25: Area code 562 went into service and names 310 as its parent.
- 2006-08-26: Area code 424 went into service as an overlay in the same area as 310.

## Nearest area codes

The area codes closest to 310, measured between the centers of the ZIP code places they serve, are 562 (about 12 miles), 747 (about 22 miles), 818 (about 22 miles), 626 (about 24 miles) and 657 (about 27 miles).

## ZIP codes

43 ZIP codes fall in places that have a rate center in this area code. The places with the most are Inglewood, CA (12 ZIP codes), Torrance, CA (10 ZIP codes) and Lakewood, CA (5 ZIP codes). A ZIP code and an area code are unrelated systems, so a ZIP code can sit in more than one area code and an area code spans many ZIP codes.

## Complaints on file

5,504 complaints for 3,708 numbers. Numbers whose latest complaint falls in each year:

- 2023: 142
- 2024: 114
- 2025: 104

## Questions

### Where is area code 310?

NANPA assigns area code 310 to California, United States.

### In which state does area code 310 sit?

California. 310 is one of 41 area codes the NANPA table assigns to the state.

### Which places does area code 310 cover?

The places with the most ZIP codes among the rate centers in 310 are Inglewood, CA, Torrance, CA and Lakewood, CA. The rate center list on this page shows all of them.

### Who owns area code 310?

NANPA assigns area codes. Within 310, Pacific Bell holds the most prefixes, 249 prefixes or 32%.

### Which time zone does 310 use?

The NANPA NPA report lists the time zone for 310 as Pacific (P).

### What year did 310 enter service?

The NANPA NPA report gives an in-service date of 1991-11-02, so 310 has been in use since 1991.

### Does area code 310 have an overlay?

Yes. 424 (in service 2006-08-26) shares the same area with 310, so numbers from all of them are local to each other.

### Which area codes are nearest to 310?

The area codes closest to 310, measured between the centers of the ZIP code places they serve, are 562 (about 12 miles), 747 (about 22 miles), 818 (about 22 miles), 626 (about 24 miles) and 657 (about 27 miles).

### How many prefixes does area code 310 have?

NANPA's report dated 2026-10-17 lists 786 prefixes in service in 310, spread over 17 rate centers and 24 holders.

### Are there complaints about 310 numbers?

The FCC data on file has 5,504 complaints for 3,708 numbers in 310. They are unverified consumer reports. A number with no complaints on file is not proven safe.

Sources: NANPA central office code report dated 2026-10-17; NANPA NPA report dated 2026-10-18; FCC unwanted-call complaints, data fetched 2026-10-17; ZIP code places from GeoNames (CC BY 4.0).