The Dry Tortugas sit about 70 nautical miles west of Key West, roughly 81 statute miles or 130 kilometers across open Gulf water. There is no shorter way to do it: the routing is essentially a straight 70 mile run past the Marquesas to Garden Key and Fort Jefferson. In a fast center console it is a long day trip out and back; many boats overnight at the Garden Key anchorage. There is no fuel and no supplies out there, so you carry the full round trip plus reserve.
Key West to Dry Tortugas distance
| Measure | Value |
|---|---|
| Straight-line distance | 70 nautical miles |
| Statute miles | 81 miles |
| Kilometers | 130 km |
| Typical on-the-water routing | about 70 nautical miles |
The run leaves Key West Harbor, passes the Marquesas Keys (your last shelter before the open water), runs past Rebecca Shoal at the midpoint, and ends at the Garden Key anchorage off Fort Jefferson. Once you clear the Marquesas there is no bail-out, so this is a commit-and-go passage that depends entirely on the weather window.
How long does it take, and how much fuel, by boat type
These are real numbers from the same engine that powers our boat fuel calculator, run over the 70 nautical mile distance at a steady cruise. They assume one continuous run one way, so treat them as the underway total for a single leg, not the round trip. Remember you have to make it back out here with no fuel dock, so double these for your tank planning. Plug in your own boat in the calculator below to get your exact figure.
| Boat | Cruise | GPH | MPG | Trip time | Fuel | Fuel cost |
|---|---|---|---|---|---|---|
| 24 ft center console (twin 150s) | 28 mph | 17.2 | 1.6 | 2 hr 53 min | 50 gal | $223 |
| 38 ft express cruiser (twin gas) | 26 mph | 43.0 | 0.6 | 3 hr 06 min | 133 gal | $600 |
| 50 ft trawler (single diesel) | 10 mph | 21.7 | 0.5 | 8 hr 03 min | 175 gal | $785 |
Fuel cost assumes $4.50 per gallon. The center console figure is for one way: the round trip burns close to 100 gallons, which is why a 120 gallon tank is the realistic minimum and a real reserve is non-negotiable on this run. Do not just scale from the table: run your own hull, load, and cruise speed.
Estimate the fuel for your own boat
The calculator below is pre-loaded with the Key West to Dry Tortugas run. Change the engine, horsepower, load, cruise speed, and tank to match your boat and it recomputes the fuel, range, and time instantly. Then double the fuel for the round trip and add reserve.
Best season and weather for the run
Best window: calmest April through June. Avoid the open run in winter cold fronts, when the Gulf builds fast and there is nowhere to hide.
This is open, exposed Gulf water with no bail-out once you are past the Marquesas. There is no fuel at the Tortugas, so carry the full round trip plus reserve. Pick a flat two day window and watch the forecast right up to departure; the right weather is the whole game on this passage.
Route notes
- Key West Harbor (0 nm): departure. Top off fuel and water here; it is the last dock you will see until you are back.
- Marquesas Keys (about 25 nm): your last shelter before the open run. Past here you are committed to the weather window.
- Rebecca Shoal (about 50 nm): mid-route light with deep water on either side, a good waypoint to confirm you are on the line.
- Garden Key anchorage (70 nm): anchor off Fort Jefferson. No fuel and no supplies out here, so arrive self-sufficient.
Gear to sort before you go
- A fuel system you trust and a real reserve calculation: this is the one run where running out is not a tow, it is a serious problem. Clean filters, a known tank gauge, and the round trip math done before you leave.
- Ground tackle sized for the open Garden Key anchorage, which can get a swell wrapping around the fort.
- A hull and gelcoat in good repair before a long offshore run with no help nearby; fix the soft spots and chips at the dock, not at sea.
Need to get the boat run-ready first? See our fuel tanks and systems and boat anchors for the gear that keeps a remote anchorage drama-free.
Plan the rest of your trip
Key West to Dry Tortugas: frequently asked questions
How far is Dry Tortugas (Fort Jefferson) from Key West, FL?
Dry Tortugas (Fort Jefferson) is about 70 nautical miles from Key West, FL, which is roughly 81 statute miles or 130 kilometers in a straight line. A typical on-the-water routing runs about 70 nautical miles.
How long does it take to get from Key West, FL to Dry Tortugas (Fort Jefferson) by boat?
A 24 ft center console (twin 150s) cruising at about 28 mph covers the 70 nautical mile run in roughly 2 hours 53 minutes. A slower trawler takes much longer, and a fast express cruiser a little less. Use the fuel calculator on this page to plug in your own boat.
How much fuel does the Key West, FL to Dry Tortugas (Fort Jefferson) trip use?
The 24 ft center console (twin 150s) burns about 50 gallons on the 70 nautical mile run at roughly 17.2 gallons per hour and 1.6 miles per gallon. Your number depends on horsepower, load, and cruise speed, so run your own boat through the calculator below.
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