Florida Keys Overseas Highway Road Trip: Miami to Key West in 3 Days
A three-day Miami to Key West drive on the Overseas Highway with mile markers for every stop, park fees, the Seven Mile Bridge and timing tips.
The drive from Miami to Key West is roughly 160 to 165 miles on US-1 and takes at least three and a half to four hours without stops, though traffic in the Keys often stretches it longer. About 113 of those miles are the Overseas Highway itself, a two- to four-lane road that hops across more than 40 bridges, including the Seven Mile Bridge. You can drive it in a day, but it works best over two or three days with a night in Islamorada or Marathon.
How mile markers work
Everything in the Keys is located by mile marker (MM), small green signs along US-1. They count down from about MM 113 at the Miami-Dade county line to MM 0 in Key West. Addresses use the same system: an address like 102601 Overseas Highway sits near MM 102.6. If a business says it's "oceanside" it's on the Atlantic side; "bayside" means the Gulf side.
Route at a glance
| Stop | Mile marker | Why stop |
|---|---|---|
| Key Largo / John Pennekamp Coral Reef State Park | MM 102.6 | Snorkel and glass-bottom boat trips to the reef |
| Islamorada | MM 72 to 84 | Sportfishing, waterfront restaurants, calm bayside sunsets |
| Long Key State Park | MM 67.4 | Quiet nature trails and kayaking |
| Curry Hammock State Park | MM 56.2 | Beach and paddling near Marathon |
| Marathon | MM 47 to 60 | Central base, Old Seven Mile Bridge access |
| Seven Mile Bridge | MM 40 to 47 | The signature drive of the route |
| Bahia Honda State Park | MM 36.8 | Some of the Keys' best natural beaches |
| Big Pine Key | MM 30.5 | National Key Deer Refuge |
| Key West | MM 0 | Old Town, sunset at Mallory Square, Dry Tortugas trips |
Day by day, three-day version
Day 1: Miami to Islamorada (about 85 miles)
Leave Miami early to clear traffic, then follow US-1 through Florida City. You can take Card Sound Road (County Road 905A) as a quieter alternate into north Key Largo; it has a small electronic toll, last reported at $1.60 for cars, collected by plate or transponder. Check Monroe County's Card Sound toll page for the current rate.
Spend the late morning at John Pennekamp Coral Reef State Park, the first undersea park in the US. Entry is $8 per vehicle plus 50 cents per person, and the park is open from 8 a.m. to sunset. Book reef snorkel tours ahead in peak season. Continue to Islamorada for the night.
Day 2: Islamorada to Marathon (about 25 to 30 miles)
This is a short driving day, so use it for the water: a kayak at Long Key State Park, a beach stop at Curry Hammock, or a fishing charter out of Islamorada. In Marathon, walk or bike the restored Old Seven Mile Bridge from Knight's Key. The 2.2-mile stretch leads to Pigeon Key, a small island with a historic railroad work camp, which you can also reach by shuttle or boat.
Day 3: Marathon to Key West (about 50 miles)
Drive the Seven Mile Bridge in daylight; it runs from roughly MM 40 to MM 47 and is the most scenic stretch of the trip. Stop at Bahia Honda State Park for a swim. Admission is $8 per vehicle for two to eight people plus a 50-cent Monroe County surcharge per person, or $4.50 for a single-occupant vehicle. On Big Pine Key, drive slowly through the National Key Deer Refuge, where the endangered deer often stand right by the road. Arrive in Key West by mid-afternoon for Old Town and sunset at Mallory Square.
Costs to plan for
| Item | Approximate cost |
|---|---|
| Fuel, one way (25 mpg car, about $3 a gallon) | About $20; check current prices |
| Card Sound Road toll (optional) | Last reported $1.60 for cars |
| John Pennekamp entry | $8 per vehicle plus $0.50 per person |
| Bahia Honda entry | $8 per vehicle plus $0.50 per person |
| Dry Tortugas National Park entrance | $15 per person (included in ferry tickets) |
| Lodging in Islamorada, Marathon or Key West | Varies widely by season; winter is the most expensive |
Add-on: Dry Tortugas from Key West
Dry Tortugas National Park sits about 70 miles west of Key West and is reachable only by ferry, seaplane or private boat. The park entrance fee is $15 per person, valid for seven days, and children 15 and under are free. Ferry tickets include the entry fee. Trips sell out in winter and spring, so book well ahead. See the National Park Service fees page for current details.
When to go
Late fall through spring brings the driest, most comfortable weather, and it's also peak season, with higher hotel prices and heavier weekend traffic. Summer is hot and humid with frequent afternoon storms. Atlantic hurricane season runs from June 1 to November 30; if you travel then, watch forecasts closely, because evacuation orders for the Keys can come with little notice and there's only one road out.
What to watch out for
- One road, real traffic. A single crash can stop US-1 for hours. Leave buffer time before flights and ferry departures.
- Speed limits change often, and they're strictly enforced in towns and on Big Pine Key, where lower nighttime limits protect Key deer.
- Parking in Key West is limited and costly; choose lodging with parking or leave the car once you arrive.
- Book state park campsites early. Bahia Honda and the other Keys parks fill months ahead in winter.
- Construction at Pennekamp: the park has noted reduced boat-trailer parking and a closed boat ramp since July 2026, which matters if you're towing a boat.
Bottom line
The Overseas Highway is short in miles but long on stops. Give it two nights, drive the Seven Mile Bridge in daylight, plan a beach stop at Bahia Honda, and leave extra time on the way back to Miami. Check current park hours and fees on the Florida State Parks site before you leave.