557 Area Code — Saint Louis, MO
Area code 557 serves Saint Louis and 1 other city in Missouri. Local time follows America/Chicago. It overlays with 314, so 10-digit dialling is required.
- State
- Missouri
- Primary city
- Saint Louis
- Timezone
- America/Chicago
- In service since
- 2024
- Type
- Overlay
- Overlay codes
- 314
Overlay of 314
Cities Served by 557
The 557 area code covers 2 cities and communities in Missouri.
- Saint Louis
- Florissant
About Area Code 557
Area code 557 is a North American Numbering Plan (NANP) area code that has been in service since 2024. It is administered by NANPA on behalf of the FCC and serves the Missouri region anchored on Saint Louis.
557 is an overlay code, which means it shares its geographic boundaries with one or more existing area codes (314). Overlays are created when a region exhausts the supply of phone numbers in its original area code. Within an overlay region, residents must dial all 10 digits even for local calls, because the same 7-digit number can exist under multiple area codes.
Mobile numbers in 557 are portable: a person who moved away from Saint Louis may still carry a 557 mobile number on their device. If you receive an unexpected call from a 557 number, run it through the reverse lookup tool above for the most accurate, free identification.
If you live or do business in Missouri, you may also interact with neighbouring or overlay codes (314). See the related codes section below to explore the rest of Missouri.
Other Missouri Area Codes
Continue exploring the Missouri numbering plan.
557 Area Code FAQ
Where is area code 557?
Area code 557 is located in Missouri, primarily serving Saint Louis and surrounding cities including Florissant. The region operates on CT (America/Chicago) time.
What state is 557 area code?
557 is a Missouri area code. It was put into service in 2024 as an overlay and shares its geographic footprint with overlay code 314.
Is 557 a scam area code?
557 is a legitimate North American area code allocated by NANPA to Missouri. Like any geographic area code, scammers sometimes spoof 557 numbers — judge each call by content (urgent demands, unfamiliar transfers) rather than the area code alone. Run the specific number through our reverse lookup if you're unsure.
What time zone does 557 use?
Area code 557 operates on CT (America/Chicago). Numbers in this area code follow standard Missouri time-zone rules including any daylight-saving transitions for that region.
Can I look up a specific 557 phone number?
Yes. Use the reverse lookup widget above to enter a full 557 number. NumLocation returns the line type (mobile, landline, VoIP), carrier, rate-center city, and any public listings tied to the number — free.
What's the difference between 557 and 314?
557 and 314 cover the same Missouri geographic area as overlay codes. Calls between them are local, but you must dial all 10 digits. New phone numbers in this region are assigned from either pool depending on what's available with the carrier at signup.