If you are investigating the 939 area code, you are looking at a telephone prefix that identifies one of the United States’ territories in the Caribbean.
The 939 area code is located in the Commonwealth of Puerto Rico, an unincorporated territory of the United States. It is a non-geographic split of the island, serving as an overlay area code to the original 787 code, meaning both prefixes cover the entirety of Puerto Rico.
This comprehensive guide will detail the exact location and coverage of the 939 area code, explain the mandatory dialing procedures required for the island, and provide crucial safety information regarding associated scam risks.
Location and Coverage of the 939 Area Code
The 939 area code was introduced on September 15, 2001, to address the rapid depletion of phone numbers in the 787 area code, which had been the island’s sole identifier since 1996.
Key Facts About Area Code 939
| Detail | Information |
| Location | Puerto Rico (Entire Archipelago) |
| Status | Overlay (Shares coverage with 787) |
| Time Zone | Atlantic Standard Time (AST) – UTC-4:00 |
| Country Code | +1 (Part of the North American Numbering Plan) |
| Dialing Rule | 10-digit dialing is mandatory for all calls. |
Major Cities in the 939 Service Area
Because 939 is an overlay code, it covers the same region as 787, including every city and municipality:
- San Juan (The capital and most populous city)
- Ponce
- Bayamón
- Caguas
- Carolina
- Mayagüez
- Arecibo
Dialing Rules and Calling the 939 Area Code
Since the introduction of the 939 overlay, Puerto Rico has mandated 10-digit dialing for all calls, a rule that must be followed whether calling a landline or a mobile phone.
How to Dial a 939 Number
- From the US/Canada: Dial 1 + 939 + 7-digit local number. (The ‘1’ is the country code).
- Within Puerto Rico: Dial 787 or 939 + 7-digit local number.
- Important: Even local calls between two numbers in San Juan must include the 3-digit area code.
Time Zone and International Call Cost
Puerto Rico observes Atlantic Standard Time (AST) at UTC-4:00 year-round. It does not observe Daylight Saving Time.
- This means Puerto Rico is typically one hour ahead of the US Eastern Time Zone (EST) during the winter, and is on the same time as US Eastern Daylight Time (EDT) during the summer months.
Scam Risk Associated with Area Code 939
While the 939 area code is legitimate, it is sometimes used in international schemes due to its affiliation with the NANP (+1 country code), which can confuse callers on the US mainland.
- The “One-Ring” Scam: Be wary of a missed call from an unfamiliar 939 or 787 number. This is a common tactic, often associated with the notorious premium-rate callback schemes, designed to trick recipients into returning the call and incurring high international or long-distance charges.
Safety Tip: As a rule of thumb, do not return calls from any number you don’t recognize in the 939 or 787 area codes. A legitimate caller will always leave a voicemail or text message.
Frequently Asked Questions (FAQ)
What is the difference between area codes 787 and 939?
The only difference is the date of assignment. Both 787 and 939 cover the exact same geographic region (all of Puerto Rico). 787 is the older code, and 939 was added as an overlay in 2001 to provide more available phone numbers.
Is calling 939 an international call?
It depends on your plan. Since Puerto Rico is part of the NANP and uses the country code +1, many US and Canadian carriers include calls to 939 as part of their standard domestic or unlimited calling packages. However, you should always verify with your carrier to avoid potential long-distance fees.
What happens if I forget to dial 10 digits in Puerto Rico?
If you dial only 7 digits (the local number) in Puerto Rico, your call will not connect. You must always dial the 10-digit number (Area Code + 7-digit number) for all calls.
Conclusion
The 939 area code is the definitive, modern identifier for Puerto Rico, serving all communications needs across the island alongside the 787 code. Whether you are conducting business or calling family, remember the mandatory 10-digit dialing rule and be mindful of the time difference in the Atlantic Time Zone.
