The 738 area code is an overlay serving San Jose and Silicon Valley in Santa Clara County. Introduced in 2024, it was layered directly on top of the established 408 and 669 codes to supply fresh phone numbers across one of the most technology-rich regions in the world.
Quick Summary of the 738 Area Code
| Area Code | 738 |
| State | California (CA) |
| Region | San Jose & Silicon Valley (Santa Clara County) |
| Major Cities | San Jose, Sunnyvale, Santa Clara, Milpitas, Gilroy, Morgan Hill, Los Gatos, Campbell |
| Time Zone | Pacific Time (PT) – PST / PDT |
| Dialing Format | 10-digit dialing required |
Geographic Coverage
The 738 area code shares an identical footprint with 408 and 669, covering San Jose and the surrounding Santa Clara County cities of Sunnyvale, Santa Clara, Milpitas, Campbell, and Los Gatos, along with Morgan Hill and Gilroy to the south. Because it is an overlay rather than a separate region, a 738 number can exist on the same street as a 408 or 669 number.
Time Zone
The 738 area code observes Pacific Time (PT) – PST / PDT. Clocks follow Pacific Standard Time (UTC−8) in winter and shift to Pacific Daylight Time (UTC−7) from mid-March through early November. All of this region is on Pacific Time. shares the same clock as the rest of California and the West Coast, so a 9:00 AM call from another California city reaches this number at 9:00 AM local time.
Tip: Business hours across the 738 region generally run 9:00 AM to 5:00 PM local time, Monday through Friday.
How to Dial a 738 Number
Because area code 738 operates as part of an overlay, 10-digit dialing is mandatory for every local and long-distance call. You must dial the full 10-digit number (738 + the seven-digit line number) even when calling a neighbor across the street. For international callers, dial your country’s exit code, then +1 (the North American country code), then 738, followed by the seven-digit local number.
Scam Alerts for the 738 Area Code
Like every U.S. area code, 738 has been used by scammers who spoof local numbers to appear trustworthy. Residents in San Jose, Sunnyvale, Santa Clara, Milpitas, Gilroy, Morgan Hill, Los Gatos, Campbell should stay alert to the following common tactics:
| Scam Type | What to Watch For |
|---|---|
| IRS / Tax Scams | Threatening calls demanding immediate tax payment via gift cards or wire transfer. |
| Utility Shut-off | Impostors claiming to be PG&E threatening to cut power. |
| Tech Support Fraud | Pop-ups or calls claiming your computer is infected and asking for remote access. |
| Job / Recruiter Scam | Fake tech-company recruiter offers seeking personal data or upfront fees. |
If you receive a suspicious call from a 738 number, take these steps to protect yourself:
- Do not share personal information such as Social Security numbers, bank details, or passwords over the phone.
- Hang up and verify by calling the organization back using an official number from its website.
- Report the call to the FTC at reportfraud.ftc.gov and to the California Attorney General’s Office.
- Block the number and consider registering with the National Do Not Call Registry.
Red Flag: Legitimate agencies such as the IRS, Social Security Administration, or your local utility company (Pacific Gas and Electric (PG&E)) will never demand immediate payment by gift card, wire transfer, or cryptocurrency. Any 738 caller making such a demand is a scammer.
History and Economy of the 738 Region
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The 738 area code entered service in 2024 as the newest overlay for the San Jose region, joining the original 408 and the 669 overlay. San Jose is the capital of Silicon Valley and one of the largest cities in the country, and the region is the global center of the technology industry, home to the headquarters of companies such as Apple, Nvidia, Cisco, Adobe, and eBay, along with a dense ecosystem of semiconductor, software, and hardware firms. Constant demand for new phone numbers from businesses and mobile users exhausted the earlier codes, prompting regulators to add 738. Because it is brand new, 738 appears almost exclusively on recently activated phone lines.
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Looking Up a 738 Number
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To identify a 738 caller, use a reverse phone lookup or search the complete 10-digit number online. Because 738 is the newest code in Silicon Valley, many numbers will have little public footprint yet, so treat unexpected 738 calls with extra caution and never share sensitive information with an unverified caller.
Nearby & Related Area Codes
California is served by several area codes. If you are researching 738, these neighboring and overlay codes are worth knowing:
You can also browse our full directory of California area codes for more regional guides.
↑ See the complete list of All US Area Codes by State – every area code across all 50 states in one directory.
Explore Neighboring States
Researching area codes just across the state line? Start with these codes in the states that border California:
Frequently Asked Questions
Where is the 738 area code located?
The 738 area code serves San Jose and Silicon Valley as an overlay of 408 and 669, covering Sunnyvale, Santa Clara, Milpitas, Campbell, Los Gatos, Morgan Hill, and Gilroy.
Why does 738 cover the same area as 408?
738 is an overlay added in 2024 because the 408 and 669 codes ran short of numbers. All three serve the exact same Santa Clara County region.
Do I have to dial 10 digits for 738?
Yes. Overlay area codes like 738 always require 10-digit dialing for local calls.
Is 738 a new area code?
Yes. Introduced in 2024, 738 is one of the newest area codes in California and observes Pacific Time (PST/PDT).
Related 738 Guides
- Worried about spam or robocalls? Browse our Scam Alerts directory.