Trainer Dawn Brancheau drowned last February when a killer whale at SeaWorld Florida dragged her underwater by her ponytail.
Officials say tens of millions of dollars have been spent on new safety features at its three parks, including rising pool floors that can lift whales and people out of the water.
There's still no timetable for having trainers swimming with whales during actual shows, and it may not happen at all, said Chuck Tompkins, curator of zoological operations for the SeaWorld parks.
For now, the orcas have to get used to having humans in the water again, Tompkins said. For instance, the animals are being retrained to swim the perimeter of the pools and ignore increasingly loud distractions created by trainers.
The first new whale show in five years, which debuts in April, is being planned to incorporate the interaction and play in the water.
The Associated Press contributed to this story.