Puerto Rico · Atlantic Time
939 Area Code
Area code 939 is in Puerto Rico, serving the entire Commonwealth of Puerto Rico. It is in the Atlantic Time zone. It shares its territory with overlay code 787, so 10-digit dialing is required.
Last updated October 1, 2026 · Source: NANPA
Where is the 939 area code?
939 is a Puerto Rico area code covering the entire Commonwealth of Puerto Rico. In the wider directory it sits in the U.S. Territories region.
Cities in the 939 area code
- San Juan
- Bayamón
- Carolina
- Ponce
- Caguas
- Guaynabo
- Arecibo
- Toa Baja
- Mayagüez
- Trujillo Alto
- Aguadilla
- Humacao
- Fajardo
939 overlay codes and dialing
The 939 territory is covered by an overlay of 2 area codes: 787, 939. All of them serve the same geographic area, and the original code is 787. Because more than one code covers the same ground, 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.
History of the 939 area code
939 went into service on September 15, 2001 as an overlay of 787, relieving number exhaustion in the San Juan area. Rather than splitting the region, the overlay lets 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 in San Juan, PR 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, covering the entire Commonwealth of Puerto Rico, in the U.S. Territories region.
What cities are in the 939 area code?
Cities in the 939 area code include San Juan, Bayamón, Carolina, Ponce, Caguas, Guaynabo, Arecibo, Toa Baja, Mayagüez and Trujillo Alto.
What time zone is 939 in?
939 is in the Atlantic Time zone.
What is the overlay for the 939 area code?
939 shares its territory with 787. Both codes (787, 939) serve the same area, so 10-digit dialing is required for every call.
When did the 939 area code start?
939 went into service on September 15, 2001 as an overlay of 787.
Do I have to dial 10 digits for 939?
Yes. Because 939 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.