Costa was a big money buy from Wolves, but struggled to live up to his billing at Leeds and spent last season out on loan at Valencia in La Liga.
The 28-year-old returned to Leeds over the summer after his loan ended, but was surplus to requirements for Whites boss Jesse Marsch.
Leeds have confirmed that Costa has now headed to Saudi Arabia to join Al-Ittihad on a loan deal.
His contract with the Yorkshire giants is due to run until the summer of 2024, but according to BBC Radio Leeds, he will join Al-Ittihad permanently following the loan.
As such, Costa’s exit from Elland Road, although on loan at present, is effectively permanent.
Leeds took time to thank Costa for the professional manner in which he has acted this summer, despite being out of the club’s plans.
The Whites said: “We would like to thank Helder for his attitude and professionalism over recent weeks and wish him luck during his time at the King Abdullah Sport City Stadium.”
Costa links up with former Wolves boss Nuno at Saudi side Al-Ittihad.
