Seaplane from Miami to Dry Tortugas

The fort is the reason the park exists and it takes up almost the whole island. Construction began in 1846 and ran for over thirty years without ever finishing it: more than sixteen million bricks, walls eight feet thick and fifty feet high, a hexagon sitting on sixteen acres of sand.

It is the largest brick masonry structure in the Americas. During the Civil War it held military prisoners, among them Dr Samuel Mudd, convicted for his part in the Lincoln conspiracy. It became a national monument in 1935 and a national park in 1992.

The moat wall runs the whole way round the outside and the walk along it is the thing most guests do first: shallow water on one side, the wall on the other and the parade ground through the arches. Self guided the whole way, so the party sets its own pace rather than joining a group.

The swimming beach sits beside the moat wall, so the water starts where the walk ends. No boat is needed for the first snorkel of the day. The coaling dock ruins lie just off the south side in shallow water and hold most of the fish life close in.

Visibility out here is what people come back for: the reefs in the park are the least disturbed in Florida and that is a direct consequence of how hard the place is to reach.

Gear travels with the party rather than being hired on arrival, because nothing is hired on arrival. Say how many are swimming when you send the date so the masks and fins are counted into the load.

The Windjammer, an iron sailing ship also known as the Avanti, lies about a mile off the north west corner of Loggerhead Key in roughly twenty feet of water. That depth is what makes it unusual: snorkellers and divers are looking at the same wreck from different heights rather than one of them waiting in the boat.

It is the best known dive in the park and one of the easier ones anywhere in the Keys. It sits away from Garden Key, so reaching it means a boat on the day rather than a swim from the beach. Worth naming when you send the date, because it changes what the afternoon needs.

Loggerhead is the westernmost island in the park and carries a lighthouse built in 1858 that is still working. It is the tall white one visible from Garden Key across the water.

The buildings on Loggerhead are closed to the public, the lighthouse included, so it is a landfall, a beach and a swim rather than a tour. The water on the way over is the reason to go: this is the clearest of it in the park.

Bush Key joins Garden Key by a sand bar and is a bird island rather than a beach. Around eighty thousand pairs of sooty terns come in to nest there, one of the largest colonies in the western hemisphere. The park closes it to visitors for the breeding season and reopens it afterwards.

The dates move from year to year and the decision is the park's rather than ours, so if the birds are the reason for the trip it is worth saying when you send the date rather than after.

The Tortugas sit on a migration route, so serious birders come at all. Spring is the window they plan around and it does not overlap neatly with the calmest water of the year.

There is a small primitive campsite on Garden Key, taken first come, first served and it is the only way to be on the island after the day boats have gone. It changes the flight rather than the paperwork.

An overnight party carries its own water for the whole stay, plus food, plus everything else and the aircraft comes back for you instead of waiting. That is a larger load out and a lighter one home and it is built into the quote rather than sorted at the dock. Say it when you send the date.

Fishing is one of the activities the park service lists for Dry Tortugas and the reason people make the trip for it is the geography rather than the regulations: the bank drops into deep water close to the islands, so the ground that would be an hour offshore anywhere else in the Keys sits within sight of the fort.

Parts of the park are set aside as a research natural area with their own rules and licences and limits are the park's business rather than ours. What is worth knowing before the date is fixed is that the boat has to come with you or be arranged out of Key West: nothing is chartered on Garden Key.

Rods and tackle travel on the aircraft within the payload for the day, the same calculation as the coolers and the water and the baggage guidance covers what that means in practice. A fishing day by seaplane elsewhere in the Keys is the easier version of the same idea.

Key West sits directly on the line between Miami and the park, seventy miles short of it, so it is the natural place to break the run.

A stop there on the way home turns one flight into two halves of a day: the fort in the morning, Duval Street and dinner in the afternoon. The packaged version of that half is the Key West escape and the route on its own is the seaplane from Miami to Key West.

The chain back east is a line of set down points rather than a single destination and the same aircraft works all of it: Big Pine Key, Marathon, Islamorada and Key Largo on the way home.

That is what turns one park run into island hopping or a fly and dine day on the way back. The full picture sits on the Florida Keys seaplane page and the island guide itself is the Dry Tortugas destination page. Anything outside the usual list goes to custom requests.