The goalkeeper arrived at Old Trafford in September 2023 with 166 career appearances and 53 clean sheets to his name, becoming Manchester United's first-ever Turkish player.

He made his Reds debut at Newport in January 2024, and played once during Euro 2024, as Turkey progressed to the quarter-finals. He was the hero in January’s Emirates FA Cup third-round victory at Arsenal in January 2025, saving penalties from Martin Odegaard and Kai Havertz. That was one of 10 appearances made by Altay during 2024/25 and he made his Premier League debut at Newcastle in April.