The Welsh club rate the midfielder highly but he is yet to make an impact at senior level, despite earning his debut in August last year.
Colwill has five senior appearances under his belt but his club are looking for options to hand him more.
The Championship club are set to send the player out on loan to League Two, where they hope he will get regular first-team action which will aid his development.
There has been interest in Colwill from Swindon Town and it is believed that Mark Kennedy’s side even went on to submit an offer for him.
However, Cheltenham Town, who were relegated from League One last season, have beaten them to Colwill.
The 19-year-old will move to Whaddon Road on loan for the entire course of the 2024/25 season.
Cardiff will be keeping a close eye on how Colwill does throughout his time at Cheltenham.
