The capital of Massachusetts and the cultural and economic heart of New England, Boston is a historic port city and a global hub for education, medicine, and finance. It is covered by the iconic 617 code and its overlay. This guide breaks down Boston’s 617 and 857 codes, the required 10-digit dialing, major ZIP codes, and the scam calls residents should watch for.
Boston Area Codes at a Glance
| Detail | Information |
|---|---|
| Primary Area Code(s) | 617 |
| Overlay Area Code(s) | 857 |
| Time Zone | Eastern Time (ET) – EST / EDT |
| Major County | Suffolk County |
| Region | Greater Boston |
| Dialing Format | 10-digit dialing required |
Area Code Breakdown & Regional Mapping
617 – Boston’s Core Code
Area code 617 is one of the original 1947 codes and is inseparable from Boston’s identity, covering the city and its closest inner-core neighbors like Cambridge, Somerville, Brookline, and Quincy. A 617 number is a prized mark of the urban core.
857 – Greater Boston Overlay
Area code 857 is the 2001 overlay for the 617 region, sharing the exact same Greater Boston geography. Many newer Boston lines carry an 857 prefix, fully local to existing 617 numbers.
Neighborhoods & Local Coverage
Boston’s 617/857 codes cover a compact, historic city of distinct neighborhoods. The colonial core runs from Downtown and Beacon Hill — along the Freedom Trail — to the brownstones of Back Bay and the South End, while the North End preserves the city’s Italian heritage near the waterfront.
The same codes reach the ballpark district of Fenway, the booming Seaport, and the residential communities of Charlestown, South Boston, Jamaica Plain, Dorchester, Roxbury, and Allston-Brighton. As the anchor of Greater Boston, the 617/857 codes also cover the inner suburbs just across the Charles River.
Local Dialing Rules & International Format
Boston and all of eastern Massachusetts have required 10-digit dialing for years — always dial the area code plus the 7-digit number. The 617 core is overlaid by 857, and the surrounding suburbs use codes such as 781/339 and 978/351.
To call Boston from outside the United States, dial your country’s exit code, then the U.S. country code +1, followed by the 10-digit number (for example, +1 617 XXX-XXXX). From inside the U.S. and Canada, simply dial 1 before the 10-digit number for long-distance calls.
Major ZIP Codes Covered
The 617 service area spans many of Boston’s core ZIP codes, including 02108, 02109, 02110, 02111, 02114, 02115, 02116, 02118, 02127, 02128, and 02134.
Spam & Scam Call Warnings in Boston
Boston residents report heavy volumes of neighbor-spoofing robocalls faking a local 617 prefix. Common scams impersonate Eversource (utility shutoff), the IRS, and the MBTA, along with fake package-delivery and toll (EZDriveMA) text scams.
| Scam Type | What to Watch For |
|---|---|
| Neighbor Spoofing | Calls that mimic a local 617 prefix to look familiar. |
| Utility / Toll Scams | Threats to shut off power or demand toll payment via gift cards. |
| IRS / Government | Robocalls claiming legal action — agencies never call to demand instant payment. |
Red flag: Any caller who pressures you to pay immediately with gift cards, wire transfers, or cryptocurrency is almost certainly running a scam. Hang up and verify through an official number.
↑ See the complete list of All US Area Codes by State for every code across the country.
Nearby & Related Massachusetts Cities
Frequently Asked Questions
What area code is Boston, MA?
Boston’s primary area code is 617, in service since 1947, overlaid by 857.
Is 857 a real Boston area code?
Yes. 857 is the FCC-approved overlay for the 617 region, added in 2001 to expand number capacity across Greater Boston.
Do I need to dial 10 digits in Boston?
Yes. All local calls in Boston and eastern Massachusetts require 10-digit dialing.
What time zone is Boston in?
Boston observes Eastern Time (EST/EDT), the same as the rest of Massachusetts.
Stay Safe & Explore More
- Verify an unknown caller in our Scam Alerts directory.
- Comparing nationwide numbers? See our Toll-Free Numbers guides.