The 31-year-old defender became a 246-appearance club icon at Bristol City before joining Middlesbrough and then Cardiff in a deal believed to be somewhere in the region of £7m last season.
He arrives to bolster a defensive pack that was been blitzed by injury in a bruising couple of weeks before the international break.
Flint has sat on the bench at Cardiff since a 6-1 New Year’s Day defeat to QPR but brings with him a reputation as one of the strongest defenders in the division. Standing at six-foot-six, he’s a threat in both boxes having scored an incredible 14 league goals for Bristol City in their promotion-winning 2014/15 season.
The Star confirmed the Owls’ interest in Flint earlier this week but understood they were facing a race against time to get a deal done, with Bluebirds boss Neil Harris seemingly ruling out a deal yesterday.
But it is understood that they pulled ahead of two Championship rivals to get the deal done and subject to paperwork, Flint goes directly into contention to feature in the Owls matchday squad at Birmingham City tomorrow.
Tom Lees and Liam Shaw are ruled out through injury, while the conditions of Dominic Iorfa and Liam Palmer are unknown.
Flint follows Jack Marriott through the player’s entrance at Hillsborough in what has already been a busy deadline day for the club.