Created in 1957 from 504 to cover Louisiana west of the Mississippi River, 318 now serves northern and central Louisiana and became an overlay complex with 457 in 2025.
The essentialsNumbering data · NumberResearch · as of 2026-09-18
Place
Shreveport
Type
geographic
Status
in service
In service since
1957
Projected exhaust
2095 Q3
Status, dates and counts are read from NumberResearch (NANPA / CNAC / FCC records). Assignment records show initial assignees, not the carrier serving a number today.
A · Where it is
Where 318 is
Northern and central Louisiana..
Communities served wholly or partly by 318:
ShreveportBossier CityMonroeAlexandriaRuston
Originally also included Lafayette, Lake Charles, New Iberia and Opelousas until the 1999 split to 337.
B · Relationships
How it relates to other codes
The codes 318 was split from, spawned, or shares its area with. A split divides the map and changes some numbers; an overlay shares the same ground and changes none — what's the difference?
Split from · 1957504New OrleansSplit from 504 in 1957, covering most of Louisiana west of the Mississippi.
Spawned · 1999337LafayetteSouthwestern/south-central Louisiana split off as 337 in 1999-2000.
Overlay · 2025457Northern Louisiana (overlay of 318)All-services overlay of the 318 area, in service Sept 25, 2025; Louisiana's first area-code overlay.
What's changing. Overlaid by 457 since Sept 25, 2025 (ten-digit dialing mandatory). Recent 2023+ code — re-check NANPA for current status.
C · History
How 318 got here
1957
Established as a split from 504, covering Louisiana west of the Mississippi from the Gulf to the Arkansas line.
Source: Wikipedia
2000-03-13
Mandatory dialing of the 337 split (southwestern Louisiana) commenced.
Source: Wikipedia
2025-08-25
Mandatory ten-digit dialing began ahead of the 457 overlay.
Source: Wikipedia
2025-09-25
457 numbers entered service, forming the 318/457 overlay complex.
Source: Wikipedia
D · Capacity
How full it is
Prefixes assigned
779
Prefixes available
21
Thousands-blocks assigned
3,582
Prefix-assignment counts describe allocation to carriers, not how many individual numbers are in use. Full technical records: NumberResearch ↗.
Live status, dates, assignment counts and exhaust forecast — data as of 2026-09-18 (CC BY 4.0).
Place, relationships and history above are compiled by North American Numbers from the sources listed and last checked 2026-09-18. A check date is not an expert review — see how this is made. Flag an error.
North American Numbers