The midfielder arrives on a season-long loan from the Bluebirds, who hold the option to recall the 24-year-old in January.
Wintle only joined Cardiff on a free transfer earlier this summer, making the move to the Welsh capital from Crewe Alexandra.
But the central midfielder, who is likely to be a replacement for the injured Grant Ward, currently finds himself down the pecking order with his new club.
“I heard of the interest a couple of days ago and I can’t wait to get going,” Wintle said of his move to Bloomfield Road.
“I know how the gaffer likes to play and I think that suits me down to the ground.
“I came here two weeks ago with Cardiff and the fans were magnificent. I can’t wait to play in front of them.”
Wintle made 186 appearances across six seasons for Crewe, having made his professional debut at the age of 18.
He's made two starts for Cardiff since making the move, both of these coming in the Carabao Cup. His one and only league appearance came off the bench in the opening day 1-1 draw against Barnsley.
Wintle becomes Blackpool' s 10th signing of the summer.
Pool’s head coach Neil Critchley said: “Ryan is an all-action midfielder with a range of passing and the capability to score a few goals as well.
“He was a stand-out performer for many seasons at Crewe and will be a good fit with the way he plays.
“I obviously know people who have worked with him and he has the right character and personality to come here and perform in the Championship.
“I’m delighted that he’s decided to join us and look forward to working with him here at Blackpool.”
The Championship transfer window closes at 11pm on Tuesday, August 31.
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