"Al Ain has signed Portuguese goalkeeper Rui Patricio to participate with the team in the 2025 Club World Cup," the club said on X about the 37-year-old Portugal international who is joining them from Atalanta.
"Patricio will arrive to the United Arab Emirates tomorrow evening to undergo medical tests and join the first-team training," Al Ain added.
Patricio played 108 matches for Portugal, helping them win Euro 2016, and has had spells with Sporting Lisbon, Wolverhampton Wanderers and AS Roma.
Al Ain, who won the AFC Champions League title in 2024, reached the final of the 2018 Club World Cup in front of their home fans.
This year's revamped 32-team tournament will take place in the United States in June and July.
Al Ain have been drawn in Group G with Juventus, Manchester City and Morocco's Wydad.
FIFA opened an exceptional transfer window from June 1st to 10th to allow players to be signed for the tournament.