The Overseas Highway runs 180 kilometres from the Florida mainland to Key West across 42 bridges, and it is the only road. There is no parallel route, no detour and no alternative. An accident or a hurricane evacuation closes the entire chain, which is the single most important thing to understand before planning around it.
The Keys are navigated by mile marker, counting down from 106 at Key Largo to zero at the corner of Whitehead and Fleming in Key West. Every address, bar and dive shop is given as an MM number, and once you adjust to it the whole chain becomes easy to read.
The quick answer
How long: four hours of driving from Miami to Key West without stopping. Two nights minimum, three or four to do it properly.
Never fly out the same day you drive back. One road, no alternative, and closures happen.
Mile markers count down from 106 at Key Largo to zero in Key West.
Key Largo for diving and the reef, Islamorada for fishing, Marathon for the Seven Mile Bridge and the turtle hospital, Big Pine for the tiny deer, Key West for everything else.
Best months: March to May. Winter is peak season and expensive, summer is hot with hurricane risk from August.
It is expensive. Accommodation runs well above mainland Florida.
Do not feed the Key deer on Big Pine. They are endangered, they are the size of a large dog, and feeding them is illegal.
The route by mile marker
Key Largo, MM 106 to 90. The diving capital. John Pennekamp Coral Reef State Park was the first undersea park in the country, with glass-bottom boat trips, snorkelling and the Christ of the Abyss statue submerged offshore. The Molasses Reef beyond it is the best diving in the chain.
Islamorada, MM 90 to 72. Sport fishing, calmer and more upmarket. Robbie’s Marina is where you feed tarpon off the dock, which is touristy and fun. Anne’s Beach is one of the few decent natural beaches in the Keys, which are otherwise short on sand because of the reef offshore.
Marathon, MM 65 to 47. The middle. The Turtle Hospital rehabilitates injured sea turtles and runs genuinely good tours that need booking. Sombrero Beach is the best swimming beach in the Keys. Immediately south is the Seven Mile Bridge, with the old bridge alongside it partly reopened as a walking and cycling pier.
Bahia Honda State Park, MM 37. The best beach in the Keys by a clear margin, with the ruined old railway bridge behind it. Arrive early because the car park fills.
Big Pine Key, MM 33. Home of the Key deer, an endangered subspecies standing under a metre tall, found nowhere else. The refuge is quiet and they are usually visible at dawn and dusk. Speed limits here are enforced strictly because of them.
Key West, MM 0. The end of the road and closer to Cuba than to Miami. Duval Street for the bars, the Hemingway Home for the six-toed cats, the Southernmost Point marker for the queue and the photograph, and Mallory Square for the sunset celebration, which is a nightly street performance rather than a formal event. The Dry Tortugas, 110 kilometres further west, are reachable by ferry or seaplane and hold a vast unfinished 19th century fort.
How long to give it
A day trip from Miami is a mistake. Four hours each way leaves you a couple of hours in Key West and no time for anything in between.
Two nights is the minimum: one somewhere in the middle Keys, one in Key West.
Three or four nights is the right version, with time to dive or snorkel at Key Largo, stop at Bahia Honda and give Key West two nights.
A week lets you add the Dry Tortugas and slow down entirely.
Driving time is deceptive. The speed limit is low, it drops sharply through the towns, and there is often traffic. Allow five hours Miami to Key West with stops, not four.
When to go
March to May is the best window: warm, dry, calm water and past the winter peak pricing.
December to February is high season, driven by visitors escaping northern winters. It is the most expensive and busiest period, though the weather is excellent.
June to September is hot, humid and the cheapest, with water temperatures at their warmest for diving.
August to October is the peak of hurricane season, and the Keys are more exposed than anywhere in Florida. Evacuation orders are issued early here because there is one road out. Book refundable rates and take insurance.
Lobster mini-season in late July brings enormous crowds for two days. Check the dates if you want to avoid it.
What it costs
Accommodation: $250 to $450 a night in Key West in season, $180 to $320 in the middle Keys, falling by a third or more between May and November.
Camping at Bahia Honda and Long Key state parks is far cheaper and books eleven months ahead to the day.
Diving: $90 to $150 for a two-tank reef dive, $60 to $90 for a snorkelling trip.
The Dry Tortugas ferry runs around $200 return and must be booked well ahead. The seaplane is roughly double.
Eating: $18 to $28 for a casual meal, $45 to $80 per person for dinner. Key lime pie is compulsory and costs $8 to $12.
Petrol is more expensive down the chain than on the mainland. Fill up before Key Largo.
Practical notes
One road, no alternative. This is the defining constraint. Accidents close the highway for hours, and there is no way around. Never schedule a flight for the same day you drive back from Key West.
Book the Dry Tortugas ferry early. It carries limited numbers and sells out weeks ahead in season.
The Keys have few beaches. The offshore reef stops sand accumulating, so most of the chain has rocky or artificial shorelines. Bahia Honda and Sombrero are the exceptions.
Reef-safe sun cream matters here more than most places, and some operators require it.
Mosquitoes and no-see-ums are severe at dawn and dusk, particularly on Big Pine and in the backcountry.
Key West parking is difficult and expensive. Once you arrive, leave the car and use the bicycle or the shuttle, since the old town is small and walkable.
Frequently asked questions
How long does it take to drive to Key West?
Four hours from Miami without stopping, and realistically five with stops and traffic. The speed limit is low and drops sharply through the towns. Give the chain two nights minimum, and three or four to do it properly.
Can you visit the Florida Keys as a day trip from Miami?
It is possible and not advisable. Four hours each way leaves you a couple of hours in Key West and no time for Bahia Honda, the Seven Mile Bridge or any diving. One night in the middle Keys transforms the trip.
What is the best beach in the Florida Keys?
Bahia Honda State Park at mile marker 37, by a clear margin, with the ruined old railway bridge behind it. Sombrero Beach at Marathon is the best in a town. The Keys generally have few beaches because the offshore reef prevents sand accumulating.
When is the best time to visit the Florida Keys?
March to May, which is warm and dry with calm water and past the winter price peak. December to February has the best weather and the highest prices. August to October is peak hurricane season and the Keys are the most exposed part of Florida.
Why should I not fly out the same day I leave Key West?
Because the Overseas Highway is the only road, across 42 bridges with no parallel route. An accident closes the entire chain for hours and there is no detour. Build in a night on the mainland before any flight.
What are the mile markers in the Keys?
A numbering system counting down from 106 at Key Largo to zero at Key West, used for every address, business and direction in the chain. Once you adjust to it, navigating the Keys becomes very simple.
Can you see Key deer in the Florida Keys?
Yes, on Big Pine Key at mile marker 33, where an endangered subspecies standing under a metre tall lives and nowhere else on earth. They are usually visible at dawn and dusk. Speed limits are strictly enforced because of them and feeding them is illegal.
Is the Dry Tortugas worth visiting?
Yes, if you can book it. It is 110 kilometres west of Key West, reachable by ferry at around $200 return or by seaplane at roughly double, and holds a vast unfinished 19th century fort with excellent snorkelling. The ferry carries limited numbers and sells out weeks ahead.
How expensive are the Florida Keys?
More than mainland Florida. Key West runs $250 to $450 a night in season and the middle Keys $180 to $320, both falling by a third or more between May and November. State park camping is the cheap alternative and books eleven months ahead to the day.
The Florida travel guide puts the Keys in context, the Everglades sit on the drive down from Miami, and the two week itinerary builds both into a southern loop.
