British-Iranian nationals Nazanin Zaghari-Ratcliffe and Anoosheh Ashoori are back in the UK after being freed from years of Iranian detention.
The pair touched down at RAF Brize Norton in Oxfordshire just after 01:00 GMT on Thursday.
Their release came after months of negotiations between the British and Iranian governments.
Ms Zaghari-Ratcliffe spent six years in detention in Iran, while Mr Ashoori was held for five.
Footage showed them chatting and looking to be in good spirits as they left the plane and made their way into a terminal together.
Ms Zaghari-Ratcliffe's husband, Richard Ratcliffe, who has campaigned tirelessly for her release, was understood to be at the airport waiting for her.
Writing on Twitter, UK Foreign Secretary Liz Truss said: "Delighted that Nazanin and Anoosheh have landed safely in the UK and are reunited with their families and loved ones. Welcome home."
The pair left Iranian capital Tehran for the UK via Oman, shortly after being freed on Wednesday.
It marked the end of an ordeal that, for Ms Zaghari-Ratcliffe, a project manager for the Thomson Reuters foundation, began in 2016 when she was accused of plotting to overthrow the Iranian government.
In April last year, she was sentenced to a further year in prison and a one-year travel ban on charges of propaganda against the government.
Mr Ashoori, a retired civil engineer, was detained in 2017 on spying charges and sentenced to 10 years in prison.
Both Ms Zaghari-Ratcliffe and Mr Ashoori have always denied the claims against them.
Their freedom comes after the UK government settled a historic debt to Iran of almost £400m, although both countries have said the payment should not be linked to the pair's release.
A second man, Morad Tahbaz, who has Iranian, UK and US nationality, was released from prison but is not yet allowed to leave Iran. Ministers have vowed to continue to push for his return home.
The 66-year-old businessman and wildlife conservationist was accused of collecting classified information about Iran's strategic areas under the pretext of carrying out environmental and scientific projects, which he denied.
Ms Truss wrote: "Pleased Morad Tahbaz has been released on furlough and is reunited with his family in Iran, but this is far from sufficient. We will continue to work intensively to secure his departure from Iran."
Speaking before Ms Zaghari-Ratcliffe's return to the UK, Mr Ratcliffe said he was "deeply grateful" for his wife's release and that it would be the "beginning of a new life" for their family.
He said their seven-year-old daughter Gabriella had picked out which toys to take to show her mother when the plane landed, and that one of the first things he would do was make his wife a cup of tea.