Area codes 318 and 457 are telephonearea codes in theNorth American Numbering Plan (NANP) for the northern and central parts of the U.S. state ofLouisiana. Area code 318 was assigned in 1957 in anarea code split of the504 numbering plan area (NPA) to nearly all of the state west of theMississippi River, stretching from theGulf of Mexico north to the border withArkansas. After reduction of the numbering plan area In 1999, in which the southern half of 318 receivedarea code 337, the numbering plan area was converted in 2025 to anoverlay complex with additional area code 457.
During the initial trials ofdirect distance dialing (DDD) in 1951, area code 318 was temporarily used as a destination code forSan Francisco.Oakland and San Francisco had separatetoll switches, so that calls had to be routed accordingly depending on 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 theGolden Gate Bridge, while calls with destinations in Oakland or the East Bay usedarea code 415. When the electromechanical card-translator became available by 1953, translations using six digits were possible; the 318 code was no longer required. The entireSan Francisco Bay Area returned to using area code 415.
In 1957, Louisiana's originally solearea code 504 was split to create a numbering plan area with area code 318 for all of the state west of theMississippi River, stretching from theGulf of Mexico north to the border withArkansas.
In 1999, the southern half, includingLafayette andLake Charles, was split off witharea code 337.[1]
Further relief planning began in 2023, as 318 was expected to exhaust by early 2026.[2] TheLouisiana Public Service Commission has approved an all-serviceoverlay complex, the first in Louisiana, with area code 457, which is scheduled to be in service on September 25, 2025.[3] A permissiveten-digit dialing period in 318 was in progress from February 24, 2025 to August 25, 2025, after which ten-digit dialing became mandatory.
| North:327/870 | ||
| West:409,430/903,936 | 318/457 | East:601/769,662 |
| South:225,337 | ||
| Arkansas area codes:479,501,870/327 | ||
| Mississippi area codes:228,601/769,662 | ||
| Texas area codes:210/726,214/469/972/945,254,325,361,409,432,512/737,713/281/832/346,806,817/682,830,903/430,915,936,940,956,979 | ||