The trio handed control of the ISS over to Russian cosmonaut Gennady Padalka, after more than 200 days in space.
Among them is Samantha Cristoforetti, who has set the record for most time in space on a single mission by a woman.
Their Soyuz spacecraft is due to undock from the ISS at 11:20 BST and land in Kazakhstan more than three hours later.
