North American Numbers Source-cited · ownership disclosed
Area code
339
In service
United States · since 2001

Boston northern/inner suburbs (overlay)

Area code 339 is an overlay of 781, serving Boston's inner and outer suburbs along the Route 128 corridor and the South Shore. It shares its entire geography with 781 and requires ten-digit dialing.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
Boston northern/inner suburbs (overlay)
Type
geographic
Status
in service
In service since
2001
Projected exhaust
2156 Q2

Status, dates and counts are read from NumberResearch (NANPA / CNAC / FCC records). Assignment records show initial assignees, not the carrier serving a number today.

A · Where it is

Where 339 is

Essex, Middlesex, Norfolk, Plymouth, and Suffolk counties (Route 128 corridor and South Shore)..

Communities served wholly or partly by 339:

WalthamWoburnLynnWeymouthDedhamMaldenMedfordRevereWakefieldLexington

Same service area as 781; the two codes are geographically identical.

B · Relationships

How it relates to other codes

The codes 339 was split from, spawned, or shares its area with. A split divides the map and changes some numbers; an overlay shares the same ground and changes none — what's the difference?

Overlay · 2001 781 Boston suburbs (Route 128 corridor) 339 overlays 781 across the same territory.
Related · 1997 617 Boston 781 (and thus 339) split from 617 in 1997; 617/857 is the encircled inner Boston area.
What's changing. Overlay of 781; ten-digit dialing mandatory. Numbers well supplied (per Wikipedia, exhaustion not projected until c. 2156).
C · History

How 339 got here

2001-05-02
Area code 339 activated as an overlay of 781; ten-digit dialing mandatory.
Source: Wikipedia
D · Capacity

How full it is

Prefixes assigned
122
Prefixes available
678
Thousands-blocks assigned
838

Prefix-assignment counts describe allocation to carriers, not how many individual numbers are in use. Full technical records: NumberResearch ↗.

Compare 339 with another code →
Sources
Wikipedia ↗
Area code 339
NumberResearch.org ↗
Live status, dates, assignment counts and exhaust forecast — data as of 2026-09-18 (CC BY 4.0).

Place, relationships and history above are compiled by North American Numbers from the sources listed and last checked 2026-09-18. A check date is not an expert review — see how this is made. Flag an error.