The 36-year-old Blind was a free agent after his contract at relegated LaLiga side Girona expired at the end of June.
Blind started his career at Ajax, making his professional debut in December 2008 and becoming a cornerstone of the team before leaving for Manchester United in 2014. After returning in 2018, Blind continued his success with the Amsterdam club, with whom he's won seven Eredivisie titles, two Dutch Cups, and two Johan Cruyff Shields.
Peculiarly, Ajax have won all of their last seven Eredivisie titles with Blind in the squad. The Amsterdam giants went trophyless in all the years since 2011 without him.
In total, Blind has played 333 games for Ajax.
"It’s great to see Daley returning to the club where it all began for him," technical director Jordi Cruyff said on the club website.
"He brings experience, composure and quality, and that can help this squad straight away. For us, this is a logical step, as someone with his background and personality fits in with what we’re trying to achieve."
Blind has signed a one-year contract in Amsterdam, where he's expected to fill a coaching role after the 2026-27 season. Blind has immediately joined Ajax's training camp in Garderen.
By returning to Ajax, Blind follows former Girona manager Michel, who signed a two-year deal with the club in June. Speaking to Flashscore earlier this year, Blind said he "really likes to work with Michel" and that he "likes his philosophy of playing. Building up from the back, with many positional changes and attractive football."