Canadian astronaut Chris Hadfield, Nasa’s Tom Marshburn and Russian Roman Romanenko landed safely in Kazakhstan.
Mr Hadfield kept hundreds of thousands of Twitter followers informed and entertained during his five months in space with pictures and even a song.
At the weekend, Mr Marshburn and fellow US astronaut Chris Cassidy conducted a spacewalk to fix an ammonia leak.
The two men replaced a suspect coolant pump, apparently stopping the leak. Without repair, science experiments on the ISS might have had to be cut back to save power.
Engineers will monitor the system to make sure there are no additional problems for the three astronauts remaining on the ISS, along with the three others who will arrive on 28 May.
The Soyuz capsule carrying the three departing astronauts landed about 150km (90 miles) south-east of the town of Zhezkazgan in central Kazakhstan at 08:31 (02:31 GMT) on Tuesday.
“The crew are feeling well,” Mission Control said in a radio transmission. Later, they were shown smiling as they waited for medical tests.
Before leaving the ISS, Mr Hadfield – the first Canadian to command the ISS – told Mission Control: “It’s just been an extremely fulfilling and amazing experience.”
On Monday, he published the first music video shot in space, a zero-gravity version of David Bowie’s hit, Space Oddity. The video went viral, and even prompted a response from Bowie: “Hallo Spaceboy.”