The drive from Miami to Key West is 160 miles and takes about 3.5 to 4 hours in normal traffic

The route runs south from Miami down the Florida Keys on US Route 1, also called the Overseas Highway. You'll cross 42 bridges, including the famous Seven Mile Bridge, and drive over water for much of the journey. The time varies based on traffic in Miami and the Keys, weather, and how many times you stop.

Most of the drive is straightforward — you stay on US 1 the entire way. The road narrows as you move south, and speed limits drop from 65 mph on the mainland to 45 mph or lower in the Keys. Construction, seasonal traffic, and occasional bridge closures can add 30 minutes to an hour to your trip.

Key Takeaways

  • The distance is 160 miles, and the drive takes 3.5 to 4 hours under normal conditions, not counting stops.
  • You'll spend most of the drive on a single road — US Route 1 — with no alternate routes once you're south of Florida City.
  • Gas costs roughly $20 to $30 for the round trip, depending on your vehicle's fuel economy and current fuel prices.
  • Peak traffic in Miami can add 45 minutes to an hour; traveling early morning or midweek is faster than afternoon or weekends.
  • The bridges and narrow road mean the drive feels longer than the mileage suggests, and fatigue is real on the return trip.

Breaking down the drive by segment

The first 30 miles from downtown Miami to Florida City take 45 minutes to an hour, depending on whether you hit rush hour. You'll drive through suburban Miami and Homestead on US 1, which is a regular highway with traffic lights and commercial areas. If you leave Miami between 7 and 9 a.m. or 4 and 6 p.m. on a weekday, expect delays.

From Florida City to Key Largo (about 60 miles) takes roughly 1.5 hours. This is where the Overseas Highway begins — you cross into the Keys and the road becomes more scenic. Speed limits are 55 mph for most of this stretch, and you'll start seeing water on both sides.

Key Largo to Marathon (about 40 miles) takes about 1 hour. This segment includes the Seven Mile Bridge, one of the most photographed bridges in the United States. The bridge itself is only 7 miles long, but the approach and exit add to the experience. Speed limits drop to 45 mph here.

Marathon to Key West (about 30 miles) takes 45 minutes to an hour. The road continues to narrow, and you're driving through smaller communities. This is the slowest segment per mile because of lower speed limits and the winding nature of the road through the Keys.

Fuel costs and vehicle wear

A round trip from Miami to Key West is 320 miles. If your vehicle gets 25 miles per gallon and fuel costs $3 per gallon, you'll spend about $38 to $40 on gas for the round trip. If your car gets 20 mpg, expect closer to $48. These numbers shift with fuel prices and your vehicle's actual efficiency.

The drive is relatively straightforward on your vehicle — it's mostly highway driving at steady speeds. However, the bridges and narrow road mean you'll use your brakes more than on a typical highway, and air conditioning runs constantly in the Florida heat. Budget an extra $5 to $10 per trip for wear and tear if you're making this drive regularly.

Traffic patterns and the best times to drive

The worst traffic is on Friday afternoons and Saturday mornings heading south, and Sunday afternoons heading north. If you're leaving Miami on a Friday after 2 p.m., add 45 minutes to your total time. The same applies to Sunday returns — the road backs up from Key West all the way to Marathon by mid-afternoon.

Weekday mornings before 10 a.m. are the fastest. Midweek drives (Tuesday through Thursday) are consistently faster than weekends. If you can leave Miami before 7 a.m., you'll avoid most congestion and reach Key West by early afternoon.

Summer (June through September) brings afternoon thunderstorms that can slow traffic, especially around Marathon. Winter (December through February) is peak tourist season, and the road is busiest. September and October are typically the slowest months for tourism, so traffic is lighter — though hurricane season is active.

What to bring and what to know about the road

Bring more water than you think you'll need. The Keys have limited services — gas stations and restaurants are spread out, especially between Marathon and Key West. Fill your tank in Florida City or Key Largo; gas prices rise as you move south, and the last station before Key West is in Marathon.

The road has no shoulder in many places, and cell service can be spotty between the islands. If your car breaks down, you may wait for a tow truck. Keep your phone charged and let someone know your route.

The bridges are narrow and have no passing lanes. If you're behind a slow vehicle, you're stuck. Don't tailgate — the road is unforgiving, and accidents block traffic for hours. Speed limits are enforced, especially through the small towns in the Keys.

Tolls and fees

There are no tolls on US Route 1 between Miami and Key West. However, if you take the Florida Turnpike to reach US 1 from other parts of Florida, you'll pay tolls on that road. The Turnpike toll from the Miami area to Florida City is roughly $3 to $5, depending on your entry and exit points.

Parking in Key West is paid parking in most areas. Expect to pay $2 to $4 per hour at metered spots, or $15 to $25 per day at parking lots. Budget this into your trip cost if you're planning to spend time in Key West.

Alternatives if you want to avoid the drive

Seaplane service runs from Miami to Key West and takes about 45 minutes. The cost is roughly $300 to $400 per person round trip, which is significantly more than driving but saves time and the physical strain of the long road. Several operators run daily flights.

The Greyhound bus runs from Miami to Key West and takes about 4.5 to 5 hours, with a stop in Marathon. The fare is typically $30 to $50 per person one way. You avoid driving fatigue but lose flexibility on timing and stops.

If you're making this trip regularly for work or frequent visits, the drive cost adds up. A round trip twice a month is $76 to $80 in gas alone, plus wear and tear. In that case, flying or busing might make financial sense.

Frequently Asked Questions

Is the drive safe at night?

The road is safe at night, but visibility is poor and fatigue is a real risk on the return trip. If you're driving back to Miami after dark, consider staying overnight in Key West or taking the drive in daylight. The narrow road and lack of shoulders make nighttime driving more stressful than daytime.

Can I make the drive in less than 3.5 hours?

Possibly, but not safely. The speed limits are 55 to 65 mph on most of the route, and they're enforced. Speeding through the Keys is dangerous — the road is narrow, bridges are tight, and there's nowhere to go if something goes wrong. Plan for 4 hours and you won't be rushed.

What's the best time of year to make this drive?

October and November are typically the best months — weather is mild, hurricane season is ending, and tourist traffic is lighter than winter. Avoid December through February if you dislike crowds. Summer brings afternoon storms, and September is the slowest month for tourism but still hurricane season.

Do I need a special vehicle to make this drive?

No. Any car that runs reliably can make the drive. The road is paved and well-maintained. Just make sure your vehicle is in good condition, your tires have tread, and your air conditioning works — you'll be running it the whole way in Florida heat.

What happens if there's a hurricane warning?

The road closes if a hurricane is approaching. The Keys are evacuated, and US 1 becomes one-way northbound. If you're in Key West when a warning is issued, you need to leave when ready. Check the National Hurricane Center forecast before you go during hurricane season (June through November).