203 Area Code — New Haven, CT
Area code 203 serves New Haven and 4 other cities in Connecticut. Local time follows America/New_York. It overlays with 475, so 10-digit dialling is required.
- State
- Connecticut
- Primary city
- New Haven
- Timezone
- America/New_York
- In service since
- 1947
- Type
- Geographic
- Overlay codes
- 475
Cities Served by 203
The 203 area code covers 5 cities and communities in Connecticut.
- New Haven
- Stamford
- Bridgeport
- Waterbury
- Norwalk
About Area Code 203
Area code 203 is a North American Numbering Plan (NANP) area code that has been in service since 1947. It is administered by NANPA on behalf of the FCC and serves the Connecticut region anchored on New Haven.
203 now shares its territory with an overlay code (475). 10-digit dialling is required for local calls within this region because the same 7-digit number can be assigned under either code.
Mobile numbers in 203 are portable: a person who moved away from New Haven may still carry a 203 mobile number on their device. If you receive an unexpected call from a 203 number, run it through the reverse lookup tool above for the most accurate, free identification.
If you live or do business in Connecticut, you may also interact with neighbouring or overlay codes (475). See the related codes section below to explore the rest of Connecticut.
Other Connecticut Area Codes
Continue exploring the Connecticut numbering plan.
203 Area Code FAQ
Where is area code 203?
Area code 203 is located in Connecticut, primarily serving New Haven and surrounding cities including Stamford, Bridgeport, Waterbury. The region operates on ET (America/New_York) time.
What state is 203 area code?
203 is a Connecticut area code. It was put into service in 1947 and shares its geographic footprint with overlay code 475.
Is 203 a scam area code?
203 is a legitimate North American area code allocated by NANPA to Connecticut. Like any geographic area code, scammers sometimes spoof 203 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 203 use?
Area code 203 operates on ET (America/New_York). Numbers in this area code follow standard Connecticut time-zone rules including any daylight-saving transitions for that region.
Can I look up a specific 203 phone number?
Yes. Use the reverse lookup widget above to enter a full 203 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 203 and 475?
203 and 475 cover the same Connecticut 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.