The Route and How Long It Takes
The Overseas Highway is the section of US-1 that runs from Florida City, just south of Miami, out to Key West. It covers about 113 miles and crosses 42 bridges, including the famous Seven Mile Bridge near Marathon. The whole thing is marked by mile markers (MM) counting down from around MM 126 in Florida City to MM 0 in Key West, and locals give directions by mile marker, so watch the green signs on the roadside.
Driven straight through, Miami to Key West is about 3.5 to 4 hours, longer on winter weekends when the road fills up. It is mostly two lanes with limited passing, so you move at the pace of traffic and cannot rush it. Get to Key Largo before you start counting on a relaxed drive. To reach the start, fly into Miami (MIA) or Fort Lauderdale (FLL) and rent a car, as our Florida airports guide covers, then follow the interstate south to Florida City.
Where to Stop Along the Way
The Keys divide into rough zones, each worth a stop. Key Largo (MM 106 to 90) is the diving and snorkeling capital, home to the reefs of John Pennekamp Coral Reef State Park. Islamorada (MM 90 to 74) is the sportfishing hub, lined with charter docks and roadside seafood. Marathon (MM 53 to 47) sits in the middle and marks the western end of the Seven Mile Bridge, a good place to break the drive and see the Turtle Hospital. Big Pine Key (MM 33 to 29) is home to the tiny Key deer.
Then comes Key West itself at the end of the road. A first-timer's pace is to spend a night midway, in Islamorada or Marathon, rather than pushing straight through both ways. That turns a rushed day into a proper trip and lets you catch a sunset over the water. Plan where to sleep with our where to stay in Florida guide, which covers the Keys' lodging options and their winter price premium.
When to Drive It
Winter, roughly December through April, is peak season in the Keys, with the best weather, the calmest water for diving, and the highest prices and heaviest traffic. Book lodging months ahead for those dates. The shoulder months of May and November give you warm weather, thinner crowds, and lower rates. Summer is hot, humid, and quiet, but it overlaps hurricane season, and the Keys are the most exposed part of Florida with only one road out.
That single road is the key safety point. If a hurricane threatens, the Keys evacuate early and US-1 backs up for hours, so never gamble on a late departure. Read our Florida hurricane season guide before booking a Keys trip between June and November, and check our best time to visit Florida guide to line up your dates with the weather you want.
Practical Tips for the Drive
Fuel up and grab supplies before you leave the mainland, since gas and groceries cost more the farther down the Keys you go. Fill the tank in Florida City or Key Largo. Drive the daylight hours if you can, both to enjoy the water views and because the two-lane road is dark and narrow at night with wildlife near Big Pine Key. Watch your speed through the residential Keys, where limits drop and enforcement is active.
Parking in Old Town Key West is tight and pricey, so many visitors park once and get around on foot, bike, or the local trolley. If the drive is not your goal, you can fly straight into Key West International (EYW) and skip US-1 entirely. But for most travelers the highway is the experience. Map the rest of your route with our getting around Florida guide before you set out.
Frequently asked questions
How long does it take to drive from Miami to Key West?
About 3.5 to 4 hours without stops, covering roughly 160 miles from Miami down US-1. It runs longer on winter weekends when traffic is heavy. Since the point of the drive is to stop along the way, most travelers give it a full day or break it overnight in Islamorada or Marathon.
How many bridges are on the Overseas Highway?
The Overseas Highway crosses 42 bridges across its 113-mile run from Key Largo to Key West. The most famous is the Seven Mile Bridge near Marathon, which spans nearly seven miles of open water between the middle and lower Keys.
What are mile markers in the Florida Keys?
Mile markers (MM) are green roadside signs counting down from about MM 126 in Florida City to MM 0 in Key West. Locals use them for all directions and addresses, so a hotel or restaurant will be listed by its mile marker rather than a street number.
Should I worry about hurricanes when driving the Keys?
Between June and November, watch the forecast closely. The Keys are the most storm-exposed part of Florida and have only one road out, so they evacuate early and US-1 backs up for hours. If a warning is issued, leave promptly and never gamble on a late departure.