Members of the public can watch their heroes train for just $5, with the money jointly going to Telethon and the Manchester United Foundation.
Manchester United will bring their entire squad to Perth in July and spend 10 days in the State as part of their pre-season training for the 2019-20 season.
The team will play friendly matches against A-League leaders Perth Glory on Saturday 13 July and then take on rivals Leeds United on Wednesday 17 July at Optus Stadium.
WACA CEO Christina Matthews said it is a very exciting opportunity to host the world's most famous football club's open training session at the WACA ground.
"It's very exciting for us here at the WACA Ground to be hosting Manchester United and to again be working in partnership with Optus Stadium to bring great events like this to Perth," Ms Matthews said.
"Manchester United were last here at the WACA Ground in the 70s so it is great to have them back again."
Click here to purchase your tickets to the open training session.