My son & I swam with the Manatees in the Crystal River last September. Since the manatees like warmer water, September isn't the best month... Winter is better, when the Gulf gets cold, and they come in to shelter in the springs.
We arrived early (pre sunrise) for a reserved program. We were the only ones on our boat. After seeing the required manatee video, we got our equipment and motored around for a bit, found a mother and baby... the baby wanted to play but the mother didn't. Saw several others, before we found one who was "playful." It was great. He wanted to be rubbed, and play. We hung out with him for about 20 minutes, and then another manatee showed up who was interested in us, but more interested in the other manatee.
We motored around for a bit longer, swam into one of the spring (wonderful) then got in the water with another group of Manatees... By now the water was getting pretty cloudy, as a Hurricane was blowing in, so we couldn't see them until they bumped us.
My brother and daughter had done the same trip the previous December.... Lots more Manatees, (Hundreds) cloudier water, much, much colder.
Homosassa, mentioned by others, is more of a zoo, with a variety of wildlife, and lots of Manatees, but you don’t get to swim with them. I believe it’s a Florida State Park, and is well worth a visit.
Randy Hees