The Cincinnati Enquirer said the zoo will have Slip and Lil' Joe transferred to Lowry Park Zoo in Tampa Oct. 17.
They will later be released through the U.S. Fish & Wildlife Service's Manatee Rescue, Rehabilitation and Release program.
Zoo Executive Drector Thane Maynard said the stars of his site's Manatee Springs exhibit will definitely be missed.
"They seem sort of like sluggish screen-savers the way they swim around so slowly. But they're big mammals, and very charismatic," he said.
Replacements for the manatees will take five months to arrive at the Cincinnati Zoo, the Enquirer reported.
Mark Campbell, director of animal health at the zoo, said Slip and Lil' Joe will spend time at the Tampa zoo learning how to survive in the wild before eventually being freed.
"They aren't going to find romaine, spinach and kale out in the wild. They're going to be finding natural vegetation, so they have to be transitioned to that," Campbell told the Enquirer.