Connecticut · Eastern Time
203 Area Code
Area code 203 is in Connecticut, serving southwestern Connecticut including Bridgeport, New Haven, Stamford and Waterbury. It is in the Eastern Time zone. It shares its territory with overlay code 475, so 10-digit dialing is required.
Last updated October 1, 2026 · Source: NANPA
Where is the 203 area code?
203 is a Connecticut area code covering southwestern Connecticut including Bridgeport, New Haven, Stamford and Waterbury. In the wider directory it sits in the Northeast region.
Cities in the 203 area code
- Bridgeport
- New Haven
- Stamford
- Waterbury
- Norwalk
- Danbury
- Greenwich
- Hamden
- Meriden
- Milford
- Stratford
- Fairfield
- West Haven
- Shelton
- Naugatuck
Counties served by 203
Fairfield County and New Haven County.
203 overlay codes and dialing
The 203 territory is covered by an overlay of 2 area codes: 203, 475. All of them serve the same geographic area, and the original code is 203. Because more than one code covers the same ground, 10-digit dialing is mandatory — you must dial the area code for every local call. New phone lines may be assigned any of these codes.
History of the 203 area code
203 is one of the original area codes assigned in 1947, when AT&T and Bell Laboratories created the North American Numbering Plan and divided the country into the first 86 numbering plan areas. It has served the Bridgeport area ever since, with 475 later added as an overlay to supply more numbers.
Is 203 a scam or spam risk?
203 is a legitimate geographic area code, not a premium or toll line, so a call from it costs you nothing extra. That said, scammers frequently spoof real local area codes to look familiar on caller ID. A genuine 203 number on your screen is no guarantee the caller is in Bridgeport, CT or trustworthy. See spam & scam-risk area codes for how spoofing works and how to respond.
Explore more
See every code in Connecticut, compare codes across the Northeast region, or view all Eastern Time codes. You can also browse the 2XX block or the complete numeric list of US area codes.
New to how this all works? Start with how area codes work, then read up on overlays, 10-digit dialing, and spam & scam-risk codes. To check another number, use the area code lookup tool.
Quick answers
203 area code FAQ
Where is the 203 area code?
The 203 area code is in Connecticut, covering southwestern Connecticut including Bridgeport, New Haven, Stamford and Waterbury, in the Northeast region.
What cities are in the 203 area code?
Cities in the 203 area code include Bridgeport, New Haven, Stamford, Waterbury, Norwalk, Danbury, Greenwich, Hamden, Meriden and Milford.
What time zone is 203 in?
203 is in the Eastern Time zone.
What is the overlay for the 203 area code?
203 shares its territory with 475. Both codes (203, 475) serve the same area, so 10-digit dialing is required for every call.
When did the 203 area code start?
203 went into service on January 1, 1947 as one of the original 1947 North American area codes.
Do I have to dial 10 digits for 203?
Yes. Because 203 is an overlay area, you must dial the full 10-digit number (area code + 7 digits) for every call.
Is 203 a toll-free or premium code?
No. 203 is a standard geographic area code, so calling it costs the same as any local or long-distance call on your plan. Toll-free calls use 800, 888, 877, 866, 855, 844 or 833.