We got there at 7, and saw tons, and got to hang out before the crowds were there. Then you get to get a kayak before anyone else - that's what I'd recommend, if you don't mind just hanging with the manatees for a couple hours.
Best to get there early ! The week you will be there it could be hard to get a parking spot ,early is best , not only for the manatees parking as well.
I also think it's better to arrive early. We was there 9 am, it was perfect.
I believe early because you'll be able to see more manatees. The water is cooler in the morning and they like the warmth given off by the power plant.
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