Why this plan is ordered by the tide, not the clock
Two reasons, and the second is the honest one.
The tide genuinely dictates the order here. The range on Amelia Island is 6 to 7.4 ft — large for Florida — and on a beach this flat that moves the waterline hundreds of yards. At low water you get a wide expanse of hard sand and the wadeable sandbars; at high water on a narrow access there is very little beach. Tides run about 50 minutes later each day, so "the morning" means nothing — the low tide does.
And we hold no confirmed opening hours. Not for a single business, museum or park on this island. So an hour-by-hour plan from us would be invented, and inventing a schedule is how people arrive at a locked door. Check today's tides, then ring anywhere you intend to eat.
Day one: the town and the fort
Follow the one-day plan — the museum, Centre Street, Fort Clinch, the beach at low water, and the sunset on the river side. That day stands on its own and it gets the postcard done.
Day two: the half most visitors miss
Behind Amelia Island are several thousand acres of tidal salt marsh threaded with creeks. It is invisible from any road, and it is the better half of the island.
Option A — get on the water. A guided kayak trip into the creeks. Dolphins are resident rather than seasonal so sightings are regular, and wading birds are close to certain. Go with an outfitter the first time: the current here is what catches people, not the distance. Go an hour either side of high water — at dead low much of the back marsh is mud rather than channel.
That is the opposite constraint from the beach, which wants low water. Two days is enough to catch both.
Option B — a boat, if paddling is not for you. Boat trips out of the marina cover the river, the marsh and Cumberland Sound. Same water, more of it, and higher up.
Option C — the marsh on foot. Egans Creek Greenway is three hundred acres of flat, free trail with alligators visible from the path and a long bird list. No booking, no tide constraint, and genuinely one of the best walks on the island. Note there is no shade at all, so not the middle of a July day.
Then the other end of the island
With the afternoon left over, drive south. American Beach was founded in 1935 as an oceanfront community where Black Americans could go to the beach during segregation — the A.L. Lewis Museum is there, and Burney Park has a free lot, restrooms and one of the quietest stretches of sand on the island.
What still does not fit
Cumberland Island — a full day, a ferry, and booking well ahead. That is what the three-day guide is for.
If it rains
Summer afternoons bring a thunderstorm most days from June to September — usually a hard hour rather than a washout. The museum, the pinball museum, the downtown bookshops and mini golf all absorb it. See rainy day.