Taking the ferry
Because the Hubbard's Marina runs the official ferry for the park (and also the cheapest, at $20 a trip), I'll focus on that one.
The ferry launches from the first pier your reach once you're inside Fort DeSoto Park — that's the one on the southeastern side of the island, not the one near historic Fort DeSoto on the southwestern side. Turn at Bay Pier and you'll see a trailer with the marina's logo printed on it.
A ferry ticket is $20 per adult, or $10 for children 11 and younger. Tips are expected from the crew, so throw in a few extra dollars
Even though ferry reservations can be booked at the outpost at the park, seats usually fill up so quickly that it's a good idea to book a reservation a few days ahead by calling Hubbard's Marina. They have been known to schedule more trips back and forth if business is booming, despite what the website says, it's a good idea to call the office anyway.
The other reason it might be valuable to book ahead of time is that making a reservation through the office lets you put the tickets on your credit card. Otherwise, hit the ATM before you go because the park kiosk is cash only. Speaking of which …
A note about cash
Before you head out for your day at Egmont Key, it's a good idea to go to an ATM and get cash. The number of cash-only purchases adds up pretty quickly, especially with multiple members of the group.
Didn't reserve your ticket? Cash. Want to do that additional snorkeling trip while out on water? Cash. Want to get a Coke and some pretzels from the boat's snack bar? Cash. Care to tip the boat captain after the trip? Cash. Do yourself a favor and stash some bills in your wallet before you get on the water.
A note about shoes
If you own decent closed-toed, treaded water shoes, this would definitely be the place to wear them. Even old sneakers would help you tromp through hot sand, coarse sea grass, palm fronds and around the island trails. The ferry discourages flip-flops on the boat, but won't stop you if they are the only shoes you brought. That said, boat ramps are steep and slippery, so better to wear treaded shoes and use your head when it comes to safety.
Egmont Key is a narrow, hot dog-shaped island just 1.6 miles long, with one side facing east into Tampa Bay, and the other side facing west out into the Gulf of Mexico.
The bayside beach isn't worth writing home about. Seaweed lines the shore. You can see industrial freighters moving in the distance. The shore is rocky, narrow and smells vaguely of seaweed and motor oil.
The ferry drops you off on the Tampa Bay side, which may wilt your optimism and expectations. But wait!
Take a quick, 10-minute walk to the Gulf side of the island, and you will discover why people put in such effort to make the trip. The beach is white and sandy, the water calm and bright blue, and the view from the shore is so expansive and unbroken that it feels like you can look across the entire Gulf of Mexico.
The key is scruffy, enduring Florida at its best, so don't expect lush tree cover and plentiful shade. The key palmettos and scrub brush thrive in the heat just fine, but visitors should bring an umbrella or extra sunscreen to endure the Florida sun.
The further you walk along the key, the more the crowds and boat traffic will thin. The old Fort Dade power plant, now reduced to pile of concrete rubble that sits along the shore, is a good marker for about halfway down the island. It's on either side of this halfway point that things will be the quietest. Then you can look out at the neverending ocean and live out your abandoned, survivalist castaway dream.
Because of the extra effort to get to Egmont Key and the no booze rule, visitors are usually people curious about this beautiful, rugged, piece of historical Florida and are less so gaggles of spring breakers ready to do keg stands on the shoreline. (Don't quote me on that If you go during spring break.) Families also come to show Egmont Key to their children and to spread out on the beach.