Area code 305 serves Miami-Dade County and part of Monroe County in the Florida Keys, and it shares that territory with the 786 and 645 overlays. The 1947 numbering plan, developed by AT&T and Bell Laboratories, originally created 86 geographic areas.
Quick answer
- 305 serves Miami-Dade County and the Florida Keys, and it is the base code for that territory.
- The mainland part of Monroe County is served by 239 according to Wikipedia; that is not yet confirmed by a PSC or NANPA record.
- Overlays 786 and 645 share the same territory. 645 numbers were first assigned August 4, 2023.
- Local calls are dialed as the area code plus the seven-digit number.
The essentials
305 area code: quick facts
| Area code | 305 |
| Coverage | Miami-Dade County and the Florida Keys (part of Monroe County) |
| State | Florida |
| Time zone | Eastern Time (ET) |
| Assigned | Original numbering plan area; the 305 assignment date is not confirmed |
| Overlay codes on the same territory | 786, 645 (August 4, 2023) |
| Mainland Monroe County | 239 (per Wikipedia; not confirmed) |
| Country code | +1 (United States) |
How 305 became Miami's code
- 1947: The North American Numbering Plan is developed by AT&T and Bell Laboratories, originally creating 86 geographic areas for the United States and Canada.
- February 2022: The Florida Public Service Commission issues an order granting an overlay plan for the 305 and 786 area codes, which adds a third code.
- August 4, 2023: Customers may be assigned 645 numbers, ahead of the expected exhaustion of central office codes in 305 and 786.
Where area code 305 is used
305 covers Miami-Dade County and the part of Monroe County that lies in the Florida Keys. The Florida Public Service Commission says 305 and 786 serve all of Miami-Dade County and the Florida Keys, and 645 co-exists with them throughout the region.
The mainland portion of Monroe County is not in the 305 territory. Wikipedia says it is served by area code 239. We did not reach a PSC or NANPA record for that point, so treat it as unconfirmed.
Wikipedia dates the addition of Monroe County to area code 786 to September 1, 2001, citing a 2001 Stuart News report. The PSC consumer summary does not restate that date, and the PSC map and 2001 filings could not be fetched. Treat 2001 as unconfirmed.
Neighboring area codes in South Florida
The table shows how 305 relates to the codes around it, so you can tell at a glance whether a number belongs to Miami-Dade or the Keys.
| Code | Where it applies | Relation to 305 |
|---|---|---|
| 305 | Miami-Dade County and the Florida Keys | Base code for the territory; 786 and 645 overlay it |
| 786 | Miami-Dade County and the Florida Keys | Overlay on 305; the Keys start date is unconfirmed (see Coverage) |
| 645 | Miami-Dade County and the Florida Keys | Overlay on 305 and 786; new numbers since August 4, 2023 |
| 954 | Broward County | Separate code for Broward; split date not confirmed |
| 239 | Mainland Monroe County | Serves the mainland part of Monroe County (per Wikipedia; unconfirmed) |
Overlay codes that share 305's territory
An overlay adds a new area code to the same geographic area, so existing numbers do not change. Two codes now share Miami-Dade and the Keys with 305:
- 786: an overlay that shares 305's territory. The 1998 installation date is not confirmed by an authority.
- 645 (August 4, 2023): a third code for the same territory. The Florida Public Service Commission approved the overlay plan that added it in February 2022.
Because the codes overlap, two neighbors on the same street can have different area codes. The area code does not show which building or office a number belongs to.
| Code | Added | Where it applies |
|---|---|---|
| 305 | Original code (date not confirmed) | Miami-Dade County and the Florida Keys |
| 786 | Overlay (date not confirmed) | Overlay on the 305 territory |
| 645 | August 4, 2023 | Overlay on the same territory as 305 and 786 |
How 305 ran short of numbers and gained overlays
Area codes run out of available numbers when the local phone numbers in them are used up. A Florida PSC order issued in February 2022 set out an overlay plan for 305 and 786 after NANPA projected that central office codes in those codes would run out during the first quarter of 2024.
Customers may be assigned 645 numbers beginning August 4, 2023. Under an overlay, current customers keep their numbers, and the new code is added alongside the old ones, as the PSC consumer summary explains.
How to dial a 305 number
North American numbers have three parts: a country code, a three-digit area code, and a seven-digit local number. Within the United States you dial the area code and number, and from outside the country you dial the country code first.
Miami-Dade and Keys customers are already in a 10-digit dialing area, so a local call uses the area code plus the seven-digit number. The Florida PSC says the 2023 overlay did not change what current customers need to do.
Using a 305 number for a Miami-Dade or Keys business
A 305 number tells callers the number was assigned in Miami-Dade or the Keys. It does not tell them where your team sits. A phone system can route 305 calls to staff in any location.
Because 786 and 645 serve the same territory, a business in the area can have numbers in any of the three codes. Routing rules should treat all three the same way.
Broward County businesses use 954, a code that is separate from 305, and Wikipedia says mainland Monroe County is served by 239 (unconfirmed). A business that serves those areas as well should set up routing for each code separately, so that a caller from Broward is not sent through the Miami-Dade rules.
Important: Whether a specific 305 number can be assigned to you depends on your phone provider and its current inventory. Confirm availability before you plan a campaign or print a number on materials.
Before you use a 305 number
- Confirm the number is available from your provider, and get its terms in writing.
- Ask who owns the number and whether it can be moved to another provider if you switch.
- Give 305, 786, and 645 numbers one routing rule, since all three serve Miami-Dade and the Keys. Treat 954 (Broward) and 239 (mainland Monroe) as separate territories.
- Set local calls to dial the area code plus the seven-digit number, as the Florida PSC consumer summary describes, before you go live.
- Expect a 645 number on the same street as an older 305 number. Overlays do not change existing numbers, so a caller's code does not show their location.
- Plan for caller ID. A local number does not prove who is calling, and caller ID can be spoofed.
Frequently asked questions
Which area is the 305 area code for?
Area code 305 serves Miami-Dade County and the part of Monroe County in the Florida Keys. Wikipedia says the mainland portion of Monroe County is served by area code 239, which is not yet confirmed against a PSC or NANPA record.
Is area code 305 being split or replaced?
No. Area code 305 is still in use. Its overlays are 786 and 645, and new 645 numbers have been assigned since August 4, 2023. All three codes cover the same territory. Broward County is served by area code 954, which is separate from 305.
Does a 305 number mean the caller is in Miami?
Not always. Caller ID can be spoofed, and the FTC warns that it can be nearly impossible to tell whether the caller ID information is real. A local-looking number is not proof of who is calling.
What time zone is area code 305 in?
Eastern Time. Miami is UTC-5 in standard time and UTC-4 during daylight saving time. Under current U.S. rules, daylight saving time starts at 2:00 a.m. on the second Sunday of March and ends at 2:00 a.m. on the first Sunday of November.
Do I have to dial the area code for a local call in Miami?
Yes. Miami-Dade and Keys customers are already in a 10-digit dialing area, so local calls are dialed as the area code plus the seven-digit number. The Florida PSC says the 2023 645 overlay did not change this, and a local call stays local regardless of the number of digits.
Can a business use a 305 number with VoIP?
Area codes describe where a number was assigned, not where the phone system runs. Whether a specific 305 number is available depends on the provider and on its inventory at the time you ask, so confirm availability before planning around one.
Sources · reviewed October 2026
Area codes 305, 786, and 645, Wikipedia
Used only for claims marked unconfirmed on this page: the September 1, 2001 addition of Monroe County to 786 (cited there to a 2001 Stuart News report) and the mainland Monroe County 239 note. The Florida PSC records that could confirm the 2001 date were not reachable. Wikipedia gives February 25, 2022 for the approval, while the PSC order is dated February 2, 2022, so this page gives the month only.
NANP history, Canadian Numbering Administrator
Used for the 1947 development of the North American Numbering Plan by AT&T and Bell Laboratories, the original 86 geographic areas, and the +1 country code.
Consumer Information Summary on 305/786 Area Code Overlay, Florida PSC
Used for the August 4, 2023 start of 645 numbers, the same-territory statement, the rule that current customers keep their numbers, the 10-digit dialing point for Miami-Dade and the Keys, and the statement that local calls stay local regardless of the number of digits.
Scammers can fake caller ID info, Federal Trade Commission
Used for the caller ID spoofing explanation, the warning that it can be nearly impossible to tell whether caller ID is real, and the advice not to rely on caller ID and not to share personal or financial information on an unsolicited call.
Used for the current U.S. daylight saving time rule: 2:00 a.m. on the second Sunday of March to 2:00 a.m. on the first Sunday of November.