"Taf is a fierce player with a huge amount of experience in Super Rugby and at Test level," Tigers coach Matt O'Connor said in a statement.
"He started Australia's recent Bledisloe Cup win over the All Blacks and was a key member of the Waratahs team that won Super Rugby in 2014.
"We think he will add a lot to a very competitive group of quality front-rowers here, working with other international players including Tom Youngs, Dan Cole, Ellis Genge and Logo Mulipola, and we look forward to his arrival next month."
Polota-Nau is named in the starting lineup for the Wallabies test against Wales in Cardiff on Saturday. The 32-year-old will join the Tigers next month.
(Reporting by Hardik Vyas in Bengaluru, Editing by William Maclean)
