But this marine creature is a robot.
"When I first saw the dolphin, I thought it could be real," said a woman who swam with the remote-controlled creature.
Edge Innovations, a US engineering company with an animatronic and special effects division in California, designed the dolphin, which cost $US26 million ($NZ39 million).
It hopes that life-like animatronics used in Hollywood movies could one day entertain crowds at theme parks, instead of wild animals held in captivity.
Swimmers could dive with robotic great white sharks or even reptiles that filled Jurassic-era seas millions of years ago.
"There are like 3000 dolphins currently in captivity being used to generate several billions of dollars just for dolphin experiences. And so there's obviously an appetite to love and learn about dolphins," said Edge Innovations founder and chief executive Walt Conti.
"And so we want to use that appetite and offer kind of different ways to fall in love with the dolphin."
Animatronics may bring back audiences turned off by parks using live animals, said Conti.
Some 20 European countries have already banned or limited the presence of wild animals in circuses.
At Edge's Hayward, California headquarters, its 250kg, 2.5-metre animatronic dolphin with skin made from medical-grade silicone headlined a programme for schools in partnership with TeachKind, part of People for the Ethical Treatment of Animals (PETA).
Edge also made the aquatic creatures used in Hollywood blockbusters Free Willy, Deep Blue Sea and Anaconda.
"The idea of this pilot is really to create a kind of "Sesame Street" under water," said Roger Holzberg, creative director for Edge's animatronic programme.
"Those characters taught a generation how to feel about different kinds of aspects of humankind in ways that had never been imagined before. And that's what we dream of with this project."
