Zaghari-Ratcliffe’s husband Richard said in a statement that she had been temporarily released on furlough from Evin Prison and was now staying at her parents' home in West Tehran.
“I am relieved that Mrs. Zaghari-Ratcliffe was today temporarily released into the care of her family in Iran,” British Foreign Minister Dominic Raab said in a statement.
Earlier this month Ratcliffe said he feared his wife had contracted coronavirus but the Iranian judiciary said she was in good health.
Nazanin's family live in Iran, but her husband lives in London.
Zaghari-Ratcliffe, a project manager with the Thomson Reuters Foundation, was arrested in Tehran in April 2016 as she was returning to Britain.
While the British media have claimed that she was arrested after a family visit, former British Foreign Secretary and current Prime Minister Boris Johnson disclosed in remarks to a parliamentary committee that Zaghari-Ratcliffe was "simply teaching people journalism as I understand it" when she was arrested at Tehran airport.