Three Sisters Springs is the centrepiece of Crystal River's manatee experience: three interconnected spring vents feeding into a glassy, crystal-clear pool in the heart of the Crystal River National Wildlife Refuge. The water stays at a constant 72°F (22°C) regardless of the season, which draws hundreds of West Indian manatees into the bay from November through March when Gulf waters cool. Swimming here — or simply floating in the gin-clear water above the vents while manatees drift past — is an experience unlike anything else in Florida.
Visitors reach the springs by kayak or canoe from the public boat ramp at Hunter Spring Park. The US Fish and Wildlife Service manages the site and enforces strict passive observation rules: no touching, no chasing, no blocking manatees from surfacing. In peak winter months, a rope barrier keeps swimmers to one side while the manatees rest on the other. Arrive early — by 8am if possible — to beat the tour groups and see manatees in the quietest part of the day.
Sources: - https://en.wikipedia.org/wiki/Three_Sisters_Springs_(Florida)