Snorkeling the river here is great. Manatees are so friendly here they will come right up to you. You can snorkel the river but you need to be a little clever about finding an entry location. There are a few parks on the river that have access. To see manatees in the river you need to go in the fall to spring when the ocean gets too cold for them. The best time is when they start coming in in the fall. We had dozens come up to us last time we were there.