The 203 area code covers southwestern Connecticut.
This article offers a comprehensive overview of the 203 area code, including where it is, what time zone it’s in, its history, and other useful information.
Understanding time zones and area codes is essential for communication, especially for businesses operating across different regions. If you do business in or plan to visit Connecticut, knowing the 203 area code time zone will help you stay connected and on schedule.
Where is the 203 area code?
The 203 area code is located in the southwestern part of Connecticut, covering major cities like Bridgeport, New Haven, Stamford, Waterbury, and Norwalk.
The bulk of the population within the 203 area code lives in three counties:
- Fairfield County: 50%
- New Haven County: 46%
- Litchfield County: 4%
If you’re calling someone in southwestern Connecticut, remember to use the 203 area code (or the 475 area code, an overlay that serves the same geographic region).
Time Zone Information for the 203 Area Code
If you’re trying to schedule a call or meeting with someone in the 203 area code, it’s a good idea to keep time zones in mind.
Primary Time Zone
The 203 area code is located within the Eastern Time Zone (ET). During the winter months, the region observes Eastern Standard Time (EST).
Daylight Saving Time (DST)
Like most of the United States, the 203 area code observes Daylight Saving Time. Here are the dates for 2025:
- DST begins on Sunday, March 9th, 2025, at 2:00 AM.
- DST ends on Sunday, November 2nd, 2025, at 2:00 AM.
During DST, the 203 area code is in the Eastern Daylight Time (EDT) zone.
Time Zone Offset
The time zone offset from Coordinated Universal Time (UTC) or Greenwich Mean Time (GMT) is -4:00 hours during Daylight Saving Time.
History of the 203 Area Code
The 203 area code is one of the original 86 area codes established in 1947 by AT&T and the Bell System. Back then, it covered the entire state of Connecticut. If you lived anywhere in Connecticut and wanted to call someone long-distance, you’d dial “203” first.
As Connecticut’s population grew, and with the rise of cell phones and pagers (remember those?), the demand for phone numbers increased. To accommodate this growth, the 203 area code was split in 1995, creating the 860 area code for the eastern and central parts of the state.
Even with that split, the 203 area code continued to experience high demand. So, in 2009, the 475 area code was introduced as an overlay. This means that the 475 area code covers the same geographic area as the 203 area code. Now, Connecticut has a total of four area codes: 203, 475, 860, and 959.
Telephone Carriers and Prefix Information
Who provides phone service in the 203 area code? Here’s a breakdown of the major players.
Landline Carriers
The biggest landline carriers in the 203 area code are:
- Southern New England Telco (42%)
- Brooks Fiber Communications Inc (5%)
- Cablevision Lightpath (5%)
- Teleport Communications America (4%)
- Global Crossing Local Services (3%)
- Verizon (3%)
- Level 3 (3%)
- Other (11%)
Wireless Carriers
The major wireless carriers serving the 203 area code are:
- Verizon (7%)
- Cingular (6%)
- Sprint (5%)
- Omnipoint Communications (3%)
- USA Mobility (2%)
- Metro PCS (1%)
- American Messaging (1%)
- Other (1%)
Prefix Usage
Prefixes in the 203 area code are almost universally assigned to a telecommunications company (99%). Here’s how those prefixes break down by type of service:
- Landline: 75%
- Wireless: 24%
- Unknown: 1%
Nearby area codes and dialing information
The 203 area code is located in Connecticut. Surrounding area codes include 860/475 (Connecticut), 914 (New York), 516 (New York), and 631/934 (New York).
Because the 203 area code has an overlay code (475), you must dial all ten digits (area code + phone number) for all calls, even local ones.
Fun fact: The 203 area code was created using “dialing pulses,” which are electrical signals that tell the phone network which number you’re dialing. Area code 203 has 15 dialing pulses. Similar area codes average about 14.1 pulses.
Closing Thoughts
The 203 area code covers southwestern Connecticut and is in the Eastern Time Zone, which observes daylight saving time.
Understanding area codes and time zones is essential for connecting with people and businesses. Knowing this information helps you communicate effectively, no matter where you are.