Mikel, 33, has earned honors during an 11-year stay at Stamford Bridge and returns to English football after a stint at the Turkish Super Lig with Trabzonspor.
“We are very happy to bring John to the club,” Stoke coach Michael O’Neill told the Potters’ official website.
“His career speaks for itself and underscores his caliber as a player.
“We spent four hours talking and made it clear that he was looking to get back in the Premier League and finish his career there, and he can do it with Stoke City.”
Mikel played more than 370 games for Chelsea after joining Norwegian Lyn in 2006.
The 91-time Nigerian midfielder, who retired from football after last year’s African Cup of Nations, won two Premier League medals in west London.
Mikel has won 3 FA Cups, the League Cup, the Champions League and the Europa League in Chelsea.
After one season in China, he joined Middlesbrough in January 2019 and made 19 appearances earlier in Turkey.
Mikel joins Morgan Fox, James Chester and Steven Fletcher in Stoke before the 2020/21 Sky Bet Championship season.