It will take some planning to get here, but it’s worth it. You’ll need a boat, your own or the ferry service, and as a result it will be one of the most expensive camping trips you’ll ever take. There’s even more expensive flight service to the island, but not for campers. If you’re camping, you’ll check in earlier than other guests and load your gear on the back of the ferry. Put your gear in tubs to protect from water on the ferry and rats on the island! Be sure to refer to the NPS rules for weight, cooking(match-light charcoal ok; compressed and liquid fuels are not), Bring plenty of water for each person, more when it’s hot. If you stay multiple nights, you’ll be able to refill water when the boat is at the dock on subsequent days.
Upon arrival, you’ll receive an orientation from the ranger. There is an open, grassy area reserved primarily for groups. Individual campsites are in the shelter of the trees to the left of the dock, near the beach and outside the fort walls. There are carts to help you take your gear to your site. If the individual sites are full, you may camp in the group area. Clean composting toilets are available except when the boat is at the dock; then you’ll use facilities on board. Breakfast and lunch are included on your arrival day; food’s available for purchase while the ferry’s in port.
Swim, snorkel, birdwatch, explore the fort, watch sunrises and sunsets. If you have a kayak and snagged one of the limited(3) spots for it on the ferry, you can make a trip to Loggerhead Key. I visited in January and had brought a shorty wetsuit so that I was comfortable snorkeling in the cooler temperatures.