Area code 203

Area code 203 New Haven, Connecticut

Area code 203 is one of the original 1947 area codes, in Connecticut, with numbers assigned in New Haven, Stamford, Bridgeport and 25 more places. It’s 12:12 AM there now.

State: Connecticut4 area codes in Connecticut
Time zone: Eastern12:12 AM there now
Exchanges: 78428 places
Overlay: 475Same area, 10-digit dialing

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Where area code 203 is

Numbers in 203 are assigned to 28 places in 3 counties: Fairfield County, New Haven County and Litchfield County.

No single place dominates: New Haven, the largest, has 18% of the exchanges.

New Haven145
Stamford97
Bridgeport94
Norwalk60
Danbury54
Waterbury52
Greenwich27
Meriden24
Westport Village16
Darien Downtown15
Fairfield University15
Wallingford Center14
Milford city14
Trumbull Center13
Branford Center10
Cheshire Village10
Old Greenwich9
New Canaan9
Guilford Center8
Wilton Center8
Woodbury Center8
Byram8
Madison Center6
Naugatuck6

Phone companies in 203

784 blocks of numbers in 203 are held by 20 phone companies. The most belong to AT&T (338), T-Mobile (72) and Verizon Wireless (61).

Mostly landline: about 50% of blocks belong to local phone and cable companies, 24% to wireless networks and 27% to other carriers.

A block’s holder is the company it was first assigned to; numbers can move to other carriers since.

History and overlays

203 has been in service since 1947, when the first North American area codes were set up.

475 (since 2009) shares the same area, so a new number there can get any of these codes and local calls are dialed with all 10 digits.

2 new exchanges were assigned since 2021, the latest in September 2024.

Calling 203

It’s 12:12 AM Eastern time in 203 right now.

From elsewhere in the U.S., dial 1, 203 and the 7-digit number; inside the area, all 10 digits too.

Nearby area codes

Connecticut has 4 area codes: 203, 475, 860 and 959.

From the North American Numbering Plan Administrator’s area code and exchange records (10/22/2026) and U.S. Census place and county names. Places and companies are where number blocks were assigned, not where anyone lives or which carrier a number uses today.

Map of the 203 area code

Map of the 203 area code around New Haven, Stamford and Bridgeport, Connecticut.

Interactive map © OpenStreetMap contributors

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Questions about 203

Where is area code 203?

In Connecticut, covering New Haven, Stamford and Bridgeport and other places across 3 counties.

What time zone is 203 in?

Eastern time. It was 12:12 AM there when this page loaded.

Is 203 an overlay?

Yes. 475 serves the same area, so dial all 10 digits for local calls.

Which phone companies have 203 numbers?

20 companies hold blocks; the most belong to AT&T, T-Mobile and Verizon Wireless. About 24% of blocks are wireless.

Is 203 running out of numbers?

Not on record. 2 new exchanges have been assigned since 2021.