Area Code Atlas

NPA 318 split from 504

Area code 318 was assigned in 1957 following a split from the original 504 area code, covering most of Louisiana west of the Mississippi River. This split reduced the territory covered by 504 to southeastern Louisiana.

NPA 337 split from 318

In 1999, the southern half of area code 318, including Lafayette and Lake Charles, was split off to create area code 337. This reduced the geographic area covered by 318.

NANP-Split of 318 Numbering Plan Area (NPA) in Louisiana; introduction of NPA 337

Area code 337 created from split of 318

On October 11, 1999, area code 337 was created in a split from area code 318. The new code covered southwestern Louisiana, while 318 continued to serve the northern and central regions.

Overlay relief for 318 approved

In May 2023, the Louisiana Public Service Commission approved an all-services distributed overlay for area code 318, introducing area code 457 to serve the same geographic area due to projected number exhaustion by early 2026. This was the first overlay complex in Louisiana.

NPA 457 overlay on 318 announced

NPA 457 to Overlay NPA 318 (Louisiana)

Network preparation and customer education for 318/457 overlay begins

On August 26, 2024, network preparation and customer education activities began for the implementation of the 318/457 overlay in northern and central Louisiana.

Permissive ten-digit dialing begins for 318/457 overlay

On February 24, 2025, a permissive ten-digit dialing period began for area codes 318 and 457. During this period, both seven- and ten-digit dialing were allowed for local calls.

Mandatory ten-digit dialing for 318/457 overlay

Mandatory ten-digit dialing began on August 25, 2025, for all calls in the 318 and 457 overlay region, ending the permissive dialing period.

Overlay of 318 with 457 begins

On September 25, 2025, area code 457 commenced service as an all-services overlay for area code 318. Both codes now serve the same geographic region in northern and central Louisiana.