The 26-year-old Koubek played 67 league games in his two seasons with Rennes and led the team to a French Cup win last season.
The value of the deal has not been disclosed.
Czech 'keeper Koubek moves from Rennes to Augsburg
Czech goalkeeper Tomas Koubek is moving from French top-flight side Stade Rennes to Bundesliga side Augsburg on a five-year deal, his agent Viktor Kolar said in a statement Tuesday.
"Augsburg was very keen and that was a major motivation for me," said Koubek, who has played nine international games for the Czech Republic.
Augsburg finished 15th in the Bundesliga last season.
