What do Beverly Hills, Santa Monica, and the Palos Verdes Peninsula have in common? They all sit inside the 310 area code, one of the most recognizable phone prefixes in the United States. It is a small patch of Southern California that punches far above its weight in cultural visibility, and the numbers behind it tell a story about how American phone networks evolved.
This guide explains where 310 actually reaches, how it was carved out of older numbering plans, why it now shares its territory with 424, and what that means for anyone dialing, moving, or doing business there.
Where the 310 Area Code Actually Reaches
The 310 area code covers the western and southern portions of Los Angeles County. Its footprint includes West Los Angeles, Santa Monica, Beverly Hills, Culver City, Torrance, and the Palos Verdes Peninsula. It is a coastal and near-coastal region rather than a single city, which is why people sometimes describe it loosely as “the Westside and the South Bay.”
That geography matters in practice. A business in Culver City and a business in Torrance may be twenty miles apart, but they share the same area code. Meanwhile, a location just a few miles east, such as downtown Los Angeles, sits in a different code entirely. Area codes follow numbering-plan boundaries, not city limits or ZIP codes, and the 310 boundary is a good example of how those two things can drift apart.
One common mistake: assuming an area code maps neatly onto a neighborhood. It does not. If someone gives you a 310 number, you know roughly which slice of Los Angeles County they are in, but you cannot pin down the exact city from the prefix alone.
The 1991 Split That Created 310
For decades, area code 213 covered essentially all of Los Angeles County. As the region’s population and phone lines exploded, that single code became unsustainable. In 1991, the numbering plan split 213, creating 310 for the western and southern portions of the county while 213 retained the central and eastern areas.
This was a significant moment in North American numbering history. The 213 code is one of the original area codes established in 1947 when the North American Numbering Plan was first drawn up. Splitting it signaled that Southern California had outgrown its original allocation.
For residents, the change meant a period of adjustment: new numbers, updated stationery, and the annoyance of telling everyone your phone number had changed. Businesses near the boundary had to decide which side of the line they fell on, and some discovered their mailing address and their phone prefix no longer matched.
1997 and the Birth of 562
The 310 region did not stay intact for long. Growth in the southeastern part of Los Angeles County, particularly around Long Beach, created pressure for another split. In 1997, area code 562 was carved out of 310 to serve that southeastern territory, with permissive dialing continuing into 1998 as callers adjusted.
Permissive dialing is worth understanding because it shows up in every area code change. During a transition window, phone networks accept both the old and new dialing patterns so that calls still connect while people update their records. It is a grace period, not a permanent arrangement.
If you have ever found an old contact card or invoice with a 310 number for a Long Beach business, this split is likely why. Numbers get reassigned and reclassified over time, and records that were never updated become misleading.
The 424 Overlay and Why 310 Still Exists
By the early 2000s, the remaining 310 territory was running short on available numbers. Rather than split the region again, regulators chose an overlay: a second area code, 424, assigned to the exact same geographic area. The overlay took effect in 2006.
An overlay works differently from a split. With a split, existing customers keep their numbers and one group of customers gets a new code. With an overlay, the original code stays in place and new numbers are issued from the new code. Both codes cover the same map. There is no geographic distinction between 310 and 424.
That has a few practical consequences:
- Existing 310 numbers stayed put. Nobody had to change their number because of the overlay.
- New lines get 424 numbers. If you request a new phone line in Santa Monica today, you will likely receive a 424 number rather than a 310 one.
- Both codes mean the same place. A 424 number and a 310 number can be next-door neighbors.
The overlay also brought a dialing change. Within the 310/424 region, callers must dial 10 digits (area code plus number) even for local calls. Dropping the area code no longer works. This is now standard across much of California and many other states, but it caught people off guard at the time.
The overlay approach has become common nationally because it is less disruptive than splitting. It avoids forcing existing customers to change numbers, which is especially valuable for businesses that have printed the number on years of marketing material. If you want a broader picture of how overlays and code-based access systems work in everyday life, the explanation of the 424 area code Los Angeles overlay walks through the same territory from the newer code’s perspective. (Best code editor for mac)
310 vs. 424: A Side-by-Side Comparison
The two codes are easy to confuse, so here is the practical difference in table form.
| Feature | 310 | 424 |
|---|---|---|
| Geographic coverage | Western/southern LA County | Identical area |
| Introduced | 1991 (split from 213) | 2006 (overlay) |
| New number assignments | Limited; mostly legacy | Primary source of new numbers |
| Dialing requirement | 10 digits | 10 digits |
| Status | Active | Active |
The key takeaway is that neither code is “better” or “more local.” They are two labels for the same place. Anyone who tells you a 424 number is somehow less legitimate than a 310 number is working from an outdated mental model.
Why 310 Carries Cultural Weight
Some area codes become status symbols, and 310 is one of them. The region it covers includes the entertainment industry’s Westside footprint, a dense cluster of tech and media companies, and some of the most expensive residential real estate in the country. That association has given 310 a certain cachet in pop culture and in business branding.
It is worth being clear about what is fact and what is reputation. The regulatory facts are simple: 310 is an area code covering a defined geography, administered like any other. The “prestige” is a cultural perception, not a rule. Still, perception has real effects. Businesses sometimes pay a premium for a 310 number because it signals a Westside presence, and some landlords and employers have historically looked at area codes as a rough proxy for local ties.
That proxy is unreliable. People keep phone numbers when they move, thanks to number portability, so a 310 number no longer proves someone lives in Santa Monica. It might just mean they got the number years ago and never changed it.
Who Manages Area Codes, and How Relief Works
Area codes are not handed out by phone companies at will. The North American Numbering Plan governs the structure of codes across the United States, Canada, and several Caribbean nations. The North American Numbering Plan Administrator (NANPA) manages the allocation of numbering resources under federal oversight, while state regulators such as the California Public Utilities Commission (CPUC) oversee area code relief proceedings within California.
When a region runs low on numbers, the process typically follows a predictable path:
- Forecast. Planners project how many numbers remain and when they will run out.
- Relief options. Regulators weigh a geographic split against an overlay.
- Public comment. Residents and businesses get a chance to respond, and overlay proposals usually draw fewer objections because nobody has to change numbers.
- Implementation. A permissive dialing period eases the transition.
The 310/424 region has not needed further relief since the 2006 overlay, based on the numbering history available. That could change as demand shifts, so anyone tracking the code for business purposes should check current regulator publications rather than relying on older articles.
Practical Tips for Living and Working With 310 Numbers
A few habits save real headaches when you deal with 310 and 424 numbers regularly.
Always store the area code. Since 10-digit dialing is mandatory in the region, saving a contact as just seven digits invites failed calls and confused text threads. Store every number in full.
Watch for stale records. Old invoices, business cards, and CRM entries may carry 310 numbers that belonged to a different city before the 1997 split. Verify before you rely on them.
Do not read too much into a prefix. Number portability means an area code is a weak signal of location. If location matters, ask directly rather than inferring from the number.
Expect 424 for new lines. If you are opening an office in the region and specifically want a 310 number, availability may be limited. Plan for a 424 number and do not treat it as a downgrade.
Check dialing rules before you travel or relocate. Ten-digit dialing is now common, but rules vary by region. A quick check prevents the small embarrassment of a call that will not connect.
The same principle of verifying how a code actually behaves applies to other code-based systems people rely on daily. If you are setting up temporary access for a rental or a delivery, for example, it helps to understand how smart lock guest code expiration works so access ends when you intend it to. Codes are only useful when you know their rules.
Common Mistakes People Make With the 310 Area Code
The most frequent error is assuming 310 and 424 are different places. They are not. A second common mistake is dialing only seven digits out of habit, which fails inside the overlay region. A third is treating a 310 number as proof of residence, which number portability has made unreliable.
Another trap: outdated directories. Online listings and old databases sometimes still show 310 numbers for businesses that moved or were renumbered after the 1997 split. Cross-check against the business’s own current contact information before you dial.
Finally, some people assume an overlay means the original code is being retired. It is not. Overlays exist precisely so the original code can keep working. Understanding that distinction clears up most confusion about the region.
Conclusion
The 310 area code is a compact piece of Southern California with an unusually eventful numbering history. Created in 1991 from a split of the original 213 code, trimmed in 1997 when 562 was carved out, and overlaid with 424 in 2006, it has been reshaped three times in three decades. Today it covers the Westside and South Bay, requires 10-digit dialing, and shares its map entirely with 424.
For anyone who lives, works, or does business in the region, the practical rules are simple: store full numbers, expect new lines to arrive as 424, verify old records, and do not treat an area code as a location certificate. The code tells you which slice of Los Angeles County a number was originally tied to. Everything else is assumption.
FAQ
What cities are in the 310 area code?
The 310 area code covers western and southern Los Angeles County, including West Los Angeles, Santa Monica, Beverly Hills, Culver City, Torrance, and the Palos Verdes Peninsula. It is a region rather than a single city, so it spans multiple municipalities and unincorporated areas.
Is 424 the same as 310?
Geographically, yes. The 424 area code is an overlay that covers the exact same territory as 310. There is no geographic distinction between them. The difference is administrative: existing customers kept their 310 numbers, while most new numbers in the region are now issued from 424.
Why do I have to dial 10 digits for a local call?
The 310/424 overlay requires 10-digit dialing, meaning the area code plus the seven-digit number, even for calls within the same neighborhood. Overlays make seven-digit dialing ambiguous because two different numbers in the same area could share the same last seven digits.
When was the 310 area code created?
The 310 area code was created in 1991 as a split of area code 213, which had previously covered all of Los Angeles County. The split divided the county into 310 for the western and southern portions and 213 for the central and eastern areas.
Can I still get a new 310 phone number?
Availability is limited. Because 310 is the original code in an overlay pair, most new number assignments in the region come from 424. Some 310 numbers may become available when existing customers release them, but a new line will typically receive a 424 number.
Does a 310 number mean someone lives in Los Angeles?
Not necessarily. Number portability lets people keep their phone numbers when they move, so a 310 number may belong to someone who no longer lives in the region. Treat the area code as a weak signal of location rather than proof of residence.
