Area codes 318 and 457

Temporary use in California During the initial trials of direct distance dialing (DDD) in 1951, area code 318 was temporarily used as a destination code for San Francisco. Oakland and San Francisco had separate toll switches, so calls had to be routed according to the final destination in the Bay Area. As the telephone equipment used at the time handled only three-digit translation, the temporary use of a distinct area code was required to distinguish between the two cities. Area code 318 was used temporarily to specify San Francisco and areas north of the Golden Gate Bridge, while calls with destinations in Oakland or the East Bay used area code 415. When the electromechanical card-translator became available in the early 1950s, translations using six digits were possible; the 318 code was no longer required. The entire Bay Area returned to using area code 415. Creation of area code 318 Louisiana was originally assigned area code 504 when the North American Numbering Plan was introduced in 1947. In 1957, area code 318 was assigned in a split of Louisiana's 504 numbering plan area. On May 5, 2023, the Louisiana Public Service Commission approved an all-services distributed overlay for the 318 numbering plan area, adding area code 457 to the same geographic region. The overlay was the first area-code overlay in Louisiana. The 457 overlay did not require existing customers to change telephone numbers or area codes. Instead, new numbers using 457 became available in the same geographic area served by 318. NANPA stated that central office codes in the 457 NPA would be available for assignment only when all assignable prefixes in the 318 NPA had been assigned. ==Dialing procedure==

Before the 457 overlay, local calls within the 318 area code could generally be completed with seven-digit dialing. The overlay required a transition to ten-digit dialing for local calls. Network preparation and customer education began August 26, 2024. A permissive ten-digit dialing period began February 24, 2025, allowing local calls to be completed with either seven or ten digits. Mandatory ten-digit dialing began August 25, 2025, after which local calls using only seven digits would not be completed. New telephone lines or services using area code 457 became available beginning September 25, 2025. Under the overlay dialing plan, local calls within the 318/457 region are dialed as ten digits. Toll calls are dialed as 1 plus the ten-digit telephone number. Operator-assisted calls, including collect, third-party and credit-card calls, are dialed as 0 plus the ten-digit number. The Louisiana Public Service Commission said that the overlay did not change existing telephone numbers, local calling areas, prices, coverage areas or other rates and services. Three-digit services such as 9-1-1, 9-8-8, 2-1-1, 3-1-1, 4-1-1, 5-1-1, 6-1-1, 7-1-1 and 8-1-1 remained available where offered. ==Service area==

The 318/457 overlay region covers northern and central Louisiana. It includes cities and towns in the Ark-La-Tex, the Red River region, the Ouachita River region and parts of central Louisiana. • Alexandria • Bastrop • Bossier City • Boyce • Bunkie • Dixie Inn • Ferriday • Farmerville • Homer • Jonesboro • Mansfield • Many • Marksville • Minden • Monroe • Natchitoches • Rayville • Ruston • Rosefield • Saint Joseph • Sarepta • Shreveport • Simmesport • Springhill • Tallulah • Vidalia • Waterproof • West Monroe • Winnfield • Winnsboro ==See also==