The goalkeeper failed to agree terms on a new contract to extend his stay at Old Trafford and will leave the club 12 years after joining from Atletico Madrid in 2011.
De Gea was close to signing a new deal only for talks to collapse at the end of season. Sources have told ESPN that United are in negotiations with Inter Milan for the transfer of Cameroon goalkeeper Andre Onana.
“I just wanted to send this farewell message to all Manchester United supporters,” De Gea wrote on social media on Saturday.
“I would like to express my unwavering gratitude and appreciation for the love from the last 12 years. We’ve achieved a lot since my dear Sir Alex Ferguson brought me to this club.
“I took incredible pride everytime I pulled on this shirt, to lead the team, to represent this institution, the biggest club in the world was an honour only bestowed upon a few lucky footballers.
“It’s been an unforgettable and successful period since I came here. I didn’t think from leaving Madrid as a young boy we would achieve what we did together.
“Now, it’s the right time to undertake a new challenge, to push myself again in new surroundings.
“Manchester will always be in my heart, Manchester has shaped me and will never leave me. We’ve seen it all.”
De Gea made 545 appearances for United — seventh on the club’s all-time list — and was part of the team which won the 2013 Premier League title under Sir Alex Ferguson. He also won the FA Cup in 2016, the Carabao Cup in 2017 and 2023 as well as the Europa League in 2017.
In a club statement released on Saturday shortly after De Gea’s announcement, manager Erik ten Hag said: “It takes great quality and character to reach the level of even playing one game for Manchester United.
“To do it 545 times over 12 years is a special achievement, particularly in the goalkeeping position where every game puts you in the spotlight. To have won player of the year awards from both the fans and his teammates, each on four occasions, shows the level of his performance and he will always be remembered as one of the very best goalkeepers in the history of the club.
“I am personally grateful for the 25 clean sheets he helped provide last season and his overall contribution on the pitch during my first year at the club.
“All the players and staff send him our very best wishes for the next phase of his outstanding career.”