Little Grey and Little White, two 13-year-old female beluga whales who were captured a decade ago and endured years of captivity, were recently returned to the sea.

The pair now resides in a bayside care pool area at the world’s first open-water beluga sanctuary in Klettsvik Bay, Iceland, which is run by nonprofit SEA LIFE Trust. Little Grey and Little White will spend several weeks getting used to their new environment before conservationists release them into the larger, nearly 345,000-square-foot and 30-foot-deep sanctuary.

Both of the 13,000-pound, 13-foot-long whales were born in the Russian Arctic, where they remained until they were two or three years old. Then, they were captured and relocated to a Russian research center. The Changfeng Ocean World aquarium in Shanghai, China subsequently acquired the whales and used them to entertain visitors, according to Newsweek.

Conservationists lobbied for and won the whales’ freedom last year, moving them 6,000 miles to a land-based facility on the Icelandic island of Vestmannaeyjar. From there, the pair reentered the ocean for the first time since 2011. SEA LIFE Trust is monitoring them closely until they’re ready for a bigger sanctuary.

“We’re absolutely delighted to be able to share the news that Little Grey and Little White are safely in their sea sanctuary care pools,” the head of SEA LIFE Trust Andy Bool said, “and are just one step away from being released into their wider, open-water home.”

The whales are not yet ready to live in the open ocean due to the many years they spent in captivity.

“We hope to show that Little White and Little Grey thrive in this bay, and we’re conducting a research study that will hopefully show that there’s a welfare benefit to being in a natural environment like this,” Bool told AFP. “We hope that can then persuade others that maybe their beluga whales might be better off in a different environment.”