United revealed on Saturday that the Netherlands international is set to join the club, with Ajax announcing the fee to be €17.5 million.
And on Sunday, Blind - who impressed for his country at this year's World Cup under now-United boss Louis van Gaal - has all but confirmed his switch to Old Trafford with an emotional post on his Instagram account.
"Want to thank everyone for the wonderful years I've had from my 7th year to 24th!" he posted. "Supporters, team-mates, staff, thanks! Ajax remains my club."
Blind won four consecutive Eredivisie titles in Amsterdam.