Puerto Rico · Atlantic Time
939 Area Code
The 939 area code is a telephone area code in Puerto Rico, covering San Juan and the surrounding area. It lies in the Atlantic Time zone.
Last updated June 5, 2026
Where is the 939 area code?
939 serves San Juan and nearby communities in Puerto Rico. In the wider directory it sits in the U.S. Territories region.
Overlay codes serving San Juan
San Juan is served by an overlay of 2 area codes: 787, 939. Because more than one code covers the same area, 10-digit dialing is mandatory — you must dial the area code for every local call. New phone lines may be assigned any of these codes, so San Juan numbers are no longer tied to a single prefix.
History of the 939 area code
939 was introduced as an overlay to relieve number exhaustion in the San Juan area, adding capacity on top of 787 rather than splitting the region. Overlays let existing customers keep their numbers while new lines draw from the added code. Learn more in our overlay guide.
Is 939 a scam or spam risk?
939 is a legitimate geographic area code, not a premium or toll line, so a call from it costs you nothing extra. That said, scammers frequently spoof real local area codes to look familiar on caller ID. A genuine 939 number on your screen is no guarantee the caller is local or trustworthy. See spam & scam-risk area codes for how spoofing works and how to respond.
Explore more
See every code in Puerto Rico, compare codes across the U.S. Territories region, or view all Atlantic Time codes. You can also browse the 9XX block or the complete numeric list of US area codes.
New to how this all works? Start with how area codes work, then read up on overlays, 10-digit dialing, and spam & scam-risk codes. To check another number, use the area code lookup tool.
Quick answers
939 area code FAQ
Where is the 939 area code?
The 939 area code is in Puerto Rico, serving San Juan and the surrounding area in the U.S. Territories region.
What time zone is 939 in?
939 is in the Atlantic Time zone.
Do I have to dial 10 digits for 939?
Yes. Because San Juan is an overlay area, you must dial the full 10-digit number (area code + 7 digits) for every call.
Is 939 a toll-free or premium code?
No. 939 is a standard geographic area code, so calling it costs the same as any local or long-distance call on your plan. Toll-free calls use 800, 888, 877, 866, 855, 844 or 833.