Reserve astronaut Sultan Al Neyadi will return on the same flight, the Mohammed bin Rashid Space Centre said early on Thursday morning. More details of his return are expected later.
The two men have spent much of this year in Star City outside Moscow and later Baikonur Cosmodrome in Kazakhstan preparing for the space mission and learning Russian, which is required for all Soyuz space missions.
Earlier, on Wednesday night, Maj Al Mansouri took part in a press conference in which he spoke hopefully of the next mission for Emirati astronauts.
"Now my mission is to transfer [my] knowledge and experience from my training in Star City and onboard the station to the next [astronaut] and I hope they will do better than me."
Asked what he would miss from his time on the ISS, he said: "My friends on-board the station; the [people] from international countries working together for mankind."