The Romania international has agreed a four-year deal with the Black Cats and will join the Premier League champions following the expiration of his contract
The Romanian becomes the Black Cats' third summer signing - after Jordi Gomez and Billy Jones - and will compete with Vito Mannone for the No.1 jersey following the expiration of his contract at the Etihad Stadium.
Pantilimon made 18 appearances for City last season, taking advantage of Joe Hart's early term slump in form, but announced his intention to leave the champions after failing to hold on to a regular starting berth.
"It is a great privilege and honour to join a club like Sunderland," he told the club's official website. "They have an amazing history and tradition and of course passionate fans.
"When I left Manchester City it was important that I chose a club with good ambition and a manager who has the hunger and desire to take the team forward.
"After speaking with the boss, I knew this was the right place and he was the right man. I can't wait to start."