781 area code — Waltham, MA geographic

Data: NANPA public reports, current as of July 28, 2026.

The 781 area code covers Waltham, Massachusetts, Eastern time zone, and dates back to September 1, 1997. It is part of the 339/781 overlay complex — these codes share the same territory. Note that porting and VoIP mean a 781 number can be used from anywhere — the code marks where the number was assigned.

767 central-office prefixes are currently active in this code, spread across 26 code-holding carriers. Thousands-block pooling applies to 596 prefixes, so a single prefix can belong to several carriers. Its prefixes map to 40 distinct rate centers.

Dialing: 10D locally, 10D to other codes (1+10 digit permissible at service provider discretion).

To check where a specific 781 number was issued, look up its six-digit prefix; to check who is actually calling, ignore the display and verify through an official callback number — caller ID is assertable and routinely spoofed.

781 was created from 617 in 1997. It has since spawned 339 (2001).

Largest localities in 781

FAQ

Is 781 a toll-free number?

No. 781 is a geographic code; calls are billed like any other domestic call. Toll-free codes are 800, 833, 844, 855, 866, 877 and 888.

Why do 339 and 781 cover the same place?

They are overlays: when a code runs low on numbers, a new code is added over the same territory instead of splitting it. The 339/781 complex shares one service area, and local calls are dialed with 10 digits.

Why am I getting spam calls from 781 numbers?

Scammers spoof recognizable area codes so calls look local or familiar. A displayed 781 number does not prove the call originated there — see our guide to spotting spoofed calls.