The 939 area code covers the same area as 787, including San Juan, Guaynabo and 72 more places in Puerto Rico.
Area code 939 is in Puerto Rico, on Atlantic Time. It has been in service since September 15, 2001. 787 covers the same area, so two neighbours can have different area codes.
- Where
- San Juan, Guaynabo and Trujillo Alto, Puerto Rico
- Time zone
- Atlantic Time
- In service since
- September 15, 2001
- Shares its area with
- 787 (since 1996)
- Prefixes in use
- 360
- How to dial
- Local calls need all 10 digits: 939-555-0142.
Find out who called you from a 939 number.
Enter the full 10-digit number to see who it is listed to, the city and state on the listing, and whether it is a mobile, landline or VoIP line. It is the same free check as our who called me lookup. To see only the caller ID name on the number, use our free CNAM lookup.
Bayamón holds 32% of the phone prefixes in area code 939.
A prefix is the three digits after the area code, and NANPA assigns each one to a town. Counting the 360 prefixes in use shows where 939 numbers are actually given out.
- Bayamón115 prefixes, 32%
- San Juan48 prefixes, 13%
- Carolina17 prefixes, 5%
- Ponce15 prefixes, 4%
- Aguadilla12 prefixes, 3%
- Caguas9 prefixes, 3%
- Trujillo Alto8 prefixes, 2%
- Manatí7 prefixes, 2%
Also served: Mayagüez, Aguadilla, Toa Baja and Fajardo and 62 smaller places.
Each prefix, or block of 1,000 numbers inside it, is also handed to a carrier. A number keeps its digits when its owner switches carrier, so the prefix no longer tells you who carries it today. Our free carrier lookup shows which carrier a 939 number is on now.
939 started in 2001 as an overlay on 787, and its ground has not changed since.
2001
939 starts on September 15, 2001, as an overlay on 787: new numbers on the same ground.
A 939 number on your screen can still be a scam, because caller ID is easy to fake.
- Let an unknown call go to voicemail. A real caller leaves a message; a robocaller usually does not.
- Look the number up with the box above before you call back, because calling back tells a robocaller your line is live.
- Hang up on anyone who wants gift cards, crypto or a wire transfer, or asks you to read out a code that was just texted to you.
- Report unwanted robocalls at reportfraud.ftc.gov, or paste a suspicious message into our free scam checker.
These are the questions people ask most about area code 939.
Where is area code 939?
939 covers San Juan, Guaynabo, Trujillo Alto and Bayamón and 70 more places in Puerto Rico.
What cities use area code 939?
The places holding the most 939 prefixes are San Juan, Guaynabo, Trujillo Alto, Bayamón, Caguas, Ponce, Carolina and Arecibo, out of 74 places in all. The count comes from NANPA's prefix assignments as of October 1, 2026.
What time zone is area code 939 in?
939 is on Atlantic Time.
When did area code 939 start?
939 went into service on September 15, 2001, as an overlay on 787: new numbers for the same area.
Is 939 the same area as 787?
Yes. 787 (since 1996) covers the same ground as 939. Nobody's number changed when it was added; new lines simply get whichever code has numbers left, so two neighbours can have different codes.
How do I dial a 939 number?
Local calls need all 10 digits: 939-555-0142.
Is 939 a toll-free number?
No. 939 is a regular area code for San Juan and Guaynabo in Puerto Rico, not a toll-free one. The toll-free codes in North America are 800, 833, 844, 855, 866, 877 and 888.
Who called me from a 939 number?
Enter the full 10-digit number in the lookup above. It returns the listed owner where there is a public record, where the number is registered, and whether it is a mobile, a landline or a VoIP line.
Is area code 939 a scam?
939 is a real Puerto Rico area code, so the code itself is not a warning sign. Scam callers fake local-looking numbers on purpose, so judge the call by what the caller asks for, and look the number up before calling back.
Source: NANPA, the North American Numbering Plan Administrator: its area code database and prefix assignments, as of October 1, 2026.