Area codes 850 and 448
Area code 850 is in use for the Florida Panhandle, including Pensacola, Tallahassee and Panama City.  Area code 904 was used for all of North Florida from 1965, when 904 split from 305, until 904 itself was split in the mid-1990s. Permissive dialing for area code 850 began June 23, 1997 and mandatory dialing began March 23, 1998.
Area code 850 was originally intended to be the relief code used in the 1995 split of the 904 area code. The Jacksonville, Tallahassee, Panama City and Pensacola LATAs, and the Florida portion of the Mobile, Alabama LATA were to retain 904 while the Daytona Beach and Gainesville LATAs changed to 850. This plan was scrapped in favor of a plan that moved only the Gainesville LATA to a new area code, this time 352 (FLA on the telephone keypad) and kept the Daytona Beach LATA in then-904 along with the rest of northern Florida. The reason for changing from 850 to 352 was a potential dialing conflict with the 407-850 office code and some rate centers in the Gainesville LATA with 7-digit local calling into the 407 area code. Political pressure from the tourism industry in Daytona Beach resulted in that area being kept in the then-904 area code.
Split from 904
Although the 1995 split was intended as a long-term solution, it only provided a small amount of relief. Within a year, 904 was on the brink of exhaustion once again. Relief planning for 904 began again in 1996. The Florida Public Service Commission had planned a three-way split of 904 to take place in 1997. The Jacksonville LATA would move to a proposed 234 area code while the Daytona Beach LATA would change to the 386 area code. The Panhandle would have retained the 904 area code. Outcry from the public and business community in the Jacksonville region was significant since Jacksonville is the largest urban area in northern Florida, and would thus face a greater expense and burden to change phone numbers, reprogram cell phones and update printed materials than other parts of the area code. When an area code is split, normal practice calls for the old area code to be retained by the largest city in the former area code territory in order to minimize disruption. There was also opposition from NANPA and the Federal Communications Commission. These two agencies objected because the split would have been unbalanced by creating a new code just for Daytona Beach. The Florida PSC changed course and adopted the plan that was ultimately implemented with the Panhandle, including Tallahassee, moving to 850 and Jacksonville and Daytona Beach retaining 904. The 234 area code has since been put into service in Ohio as an overlay to area code 330.
Area code 850 is projected to exhaust in the first quarter of 2022. Based on this forecast, NANPA has begun relief planning to provide additional numbering capacity in the 850 region. An initial planning meeting was held on May 16, 2019, where industry members recommended an all-services overlay as the preferred relief method. NANPA has subsequently filed a request with the Florida Public Service Commission to approve a new area code overlaying 850. The new area code, 448, would be placed into service in 2021, ahead of the projected exhaust of 850. Ten-digit dialing of local calls will be required.
The Florida Public Service Commission approved the industry's all-services overlay recommendation at its November 5, 2019 conference. The new area code, 448, has been officially assigned to overlay 850. 
Cities served by the 850 area code
- DeFuniak Springs
- Fort Walton Beach
- Gulf Breeze
- Lynn Haven
- Miramar Beach
- Mossy Head
- Panama City
- Port Saint Joe
- Tallahassee (State Capital)
- Deak, James N. (1997-05-12). "North American Numbering Plan Planning Letter PL-NANP-059" (PDF). National NANPA (PDF of a scanned image, not searchable text). Retrieved 2019-05-02.
|Florida area codes: 239, 305/786, 321, 352, 386, 407, 561, 727, 754/954, 772, 813, 850, 863, 904, 941|
|North: 229, 251, 334|
|West: 251||area code 850||East: 352, 386|
|South: Gulf of Mexico|
|Alabama area codes: 205, 251, 256/938, 334|
|Georgia area codes: 229, 404, 470/678, 478, 706/762, 770, 912|