Rick Munarriz, a theme park analyst for The Motley Fool, a company that advises investors, said people have not forgotten about the film, but its effect has worn off.
"SeaWorld is back. You don't grow attendance 8 percent year-over-year for all four quarters in 2018 and not be back," he said. "It's been quicksand for SeaWorld since 2013, and it got a rope. It's starting to claw its way out."
The company's revenue was up by more than $100 million in 2018 and attendance increased by 1.8 million visitors.
Munarriz said SeaWorld has shifted its focus from animal performances to rides and other types of shows.
"SeaWorld is saying, 'We wanted to add more rides. We know there's not a Six Flags in Florida,'" he said.
Munarriz said special events, such as the Seven Seas Food Festival, has drawn visitors and got them to spend more money at the parks.
"Now they're saying, 'Let's just get 'Sesame Street.'' Who could hate Big Bird?" Munarriz said. "PETA is not going to be protesting Oscar the Grouch being kept inside a garbage can."
SeaWorld Chief Operating Officer John Reilly also credited the company's rebound to more effective pricing strategies and marketing and a focus on efficiency.