939

Area code 939 is a significant part of the telephone numbering plan in a specific region outside the continental United States. Geographical Coverage: Area code 939 serves Puerto Rico, a territory of the United States located in the Caribbean. It operates as an overlay for the existing area code 787. This means that it covers the same geographic area as 787, encompassing the entire island. Introduction as an Overlay Code: The 939 area code was introduced in 2001 to provide additional numbering resources for Puerto Rico. The demand for phone numbers had increased significantly, especially due to the proliferation of cell phones and other communication devices. Overlaying 939 with the existing 787 area code allowed for more phone numbers without changing the existing numbers. Impact on Dialing Patterns: With the introduction of the 939 overlay, 10-digit dialing (area code + phone number) became mandatory for all calls within Puerto Rico. This change was necessary to accommodate the overlay system and ensure efficient allocation and usage of phone numbers. In conclusion, area code 939 plays a vital role in Puerto Rico's telecommunication infrastructure, reflecting the island's expansion and the evolving needs for more telephone numbers. Its implementation as an overlay area code is a testament to the dynamic growth and technological advancement in Puerto Rico's telecommunication landscape.