Eight dolphins which once performed at the US National Aquarium in Baltimore will be retired from their tanks to a seaside sanctuary.
The Maryland aquarium is announcing plans to move its Atlantic bottlenose dolphins into a protected habitat by the end of 2020.
Seven of the dolphins were born in captivity, and aquarium CEO John Racanelli said the animals will remain in human care in the sanctuary.
The aquarium has not yet settled on a location.
It has been considering new options for its dolphins for several years amid growing public distaste for live animal shows.
The dolphins stopped scheduled performances in 2012, but remain on display.
SeaWorld is making similar changes to its killer whale shows, but has stopped short of releasing orcas or dolphins into the ocean.
Animal rights activists have applauded the National Aquarium for the move.
People for the Ethical Treatment of Animals (Peta) criticised SeaWorld earlier this year for not releasing its killer whales from their tanks.
Peta executive vice president Tracy Reiman said the Baltimore aquarium's step could prompt other institutions to retire their dolphins and orcas to sanctuaries as well.
She said the aquarium recognised "the needs of intelligent, far-ranging dolphins" are not met in captivity.
The US Association of Zoos and Aquariums said each of its members makes decisions "appropriate for the animals" in its care.
In a statement, interim president and CEO Kris Vehrs said the National Aquarium will work with state and federal agencies as it moves forward with the dolphins' relocation.