The 20-year-old full-back has joined the Championship side on a season-long deal, becoming Bristol City boss Michael Skubala's ninth signing of the summer.
Cardines, who can operate at full-back or wing-back, made his senior breakthrough at Palace last season and won a UEFA Conference League winner's medal as an unused member of the squad that beat Rayo Vallecano in the final. He also started against Arsenal in the Premier League, the club where he began his youth career before switching to Palace at Under-16 level in 2022.
He has become a regular under the Trinidad and Tobago flag too, winning 11 caps since his senior call-up last year.
Skubala's sporting director, James Ellis, said Cardines had "an excellent pedigree" and would add "dynamism and positive quality" to a Bristol City backline light on depth in the wide areas. Cardines will spend the campaign trying to force his way into a regular starting role at Ashton Gate, with Palace's academy staff understood to have been closely involved in identifying the move as the right next step in his development.
A second Crystal Palace youngster looks set to follow him out of Selhurst Park, though in very different circumstances. Centre-back Mofe Jemide, 19, is in advanced talks over a permanent transfer to Alverca, who won promotion to Portugal's Primeira Liga last season and are backed by an ownership consortium that includes Real Madrid forward Vinícius Júnior.
Jemide, who joined Palace's academy from Barnet and has represented England up to Under-20 level, has been offered a three-year contract at the Lisbon-area club. He has yet to make a senior appearance for Palace, having spent this season and last with Darren Powell's Under-21 side in Premier League 2, but interest in the teenager has been consistent: Chelsea had an approach for him turned down last year, and he has previously been the subject of transfer speculation involving PSV and Austria's LASK.
Should the Alverca deal go through, it would mark Palace's second significant academy departure of the day and underline the pulling power the south London club's youth pipeline now carries across Europe.