National park · Florida Keys
Dry Tortugas: the fort, the ferry and the clearest water in Florida
Fort Jefferson stands on a sand key 110 kilometres west of Key West.
- The activity
- A national park of seven small keys around Fort Jefferson, an immense unfinished nineteenth-century coastal fort, reached only by boat or seaplane.
- Location
- About 113 kilometres, or 70 miles, west of Key West in the Gulf of Mexico.
- Duration
- A full day on a fixed schedule: check-in at 7am, boarding 7.30am, departure 8am, arriving Fort Jefferson at 10.30am. The fort tour runs at 11am, lunch from 11am to 1pm, departure at 3pm and back in Key West at 5.30pm.
- Best time to arrive
- Check in by 7am; the ferry does not wait. Book well ahead, since the Yankee Freedom is the only vessel authorised by the National Park Service and sailings sell out weeks and often months in advance.
- Admission cost
- From about $250 per adult, covering the round-trip crossing, the park entrance fee, breakfast, lunch, snorkelling equipment and the guided tour of Fort Jefferson. Parking in Key West is extra, around $32 a day at the Grinnell Street garage, and there is no free parking nearby.
- The day
- The ferry leaves Key West at 8am, arrives at Garden Key around 10.30am, departs the island at 3pm and is back in Key West by about 5.30pm. That gives roughly four and a half hours ashore.
- What the fare includes
- Park entrance, breakfast and lunch, snorkel equipment and a guided tour of the fort, usually at 11am. National park pass holders are refunded the entrance portion at check-in.
- Snorkelling
- The moat wall and the surrounding shallows hold coral, reef fish and often turtles. Water clarity is the best in Florida when the wind is down.
- Booking
- The ferry carries a limited number of passengers a day and sells out weeks ahead in high season. The adult fare is around $250 in 2026. The seaplane is faster and considerably more expensive.
What to expect
The ferry crossing is two and a half hours each way across seventy miles of open water, and it is part of the experience rather than transport. Breakfast and lunch are served on board, and the crew narrates the run out past the reef line.
Fort Jefferson is the reason the park exists: a hexagonal nineteenth-century coastal fort of sixteen million bricks, the largest masonry structure in the Americas, never finished and never fully armed. A guided tour of the walls and the moat is included, and you can walk the upper terreplein alone afterwards.
The snorkelling is the surprise. The moat wall and the coaling docks hold coral, reef fish and often nurse sharks and turtles, in shallow, sheltered water reached directly from the beach. Equipment is included.
Garden Key gives you about four and a half hours ashore, and there is nothing on it: no shops, no shade beyond the fort, and the only water is what the ferry provides. That emptiness is the point, and it is why the island feels remote in a way nowhere else in Florida does.
The honest takeaway
One of the best-reviewed days in Florida, with reservations focused on cost, the crossing and the difficulty of booking.
What visitors praise
- Exceptional water clarity. Reviewers consistently describe it as the clearest snorkelling they have found in the United States.
- The fort is extraordinary. Scale, isolation and condition combine into something no other Florida site matches.
- Genuinely uncrowded. Daily visitor numbers are capped by boat capacity.
- Inclusive fare. Meals, park fee and snorkel equipment are all covered by the ferry ticket.
What visitors find difficult
- Expensive. The ferry is the most costly single excursion in the Keys.
- The crossing can be rough. On windy days the seventy-mile passage is felt, so take something for seasickness before boarding.
- Books out early. Daily capacity is capped and same-week availability in winter and spring is rare.
- No shade or services on the island. Beyond the fort itself there is very little infrastructure.
Drawn from the recurring themes in public visitor reviews of the activity and the tours that reach it. We do not reproduce individual reviews or aggregate scores; for current ratings, check Viator or another booking platform directly.
Getting there
The ferry departs from the Key West Bight ferry terminal in the morning and requires check-in well before sailing. Parking in Old Town is limited, so allow extra time or use a taxi.
Seaplane charters from Key West International Airport reach the park in about forty minutes and offer half-day and full-day options, at a considerably higher price.
How to make the most of the day
- 1Book weeks in advance. This is the single most important piece of advice for the Dry Tortugas.
- 2Take motion sickness medication before boarding. Once the crossing is underway it is too late.
- 3Do the guided fort tour at 11am, then snorkel. The tour runs on a fixed schedule; the water does not.
- 4Bring more sun protection than you think you need. There is almost no shade outside the fort.
- 5Walk the full moat loop. It is short, and the fish life along the wall is best on the far side.
A little more background
Fort Jefferson was begun in 1846 to control the shipping channel between the Gulf and the Atlantic, and was never completed. It later held prisoners, including Dr Samuel Mudd, convicted in connection with the Lincoln assassination. Roughly sixteen million bricks were shipped out to build it, on an island with no fresh water of its own. Around 65,000 people visit the park each year, most of them for a single day.
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