Calvin Wellington, Liam Cooper and Jonah Cunningham - son of former Saints' boss Keiron Cunningham - have all joined Sheffield Eagles on loan for the rest of the season.
The St Helens trio have made the move to gain more game time but remain available for the Reserves if not selected by the Eagles.
Of the threeo, Calvin is the only one with Super League experience.
The Welsh centre made his debut against Huddersfield at the Magic Weekend in 2016.
Liam is a second rower who captained the Academy side to the Under 19s Championship last season while utility forward Jonah has appeared 10 times for the Reserves this year.
Saints' chief executive officer Mike Rush said: “The loan deals for Calvin, Liam and Jonah are a vital part of their development.
“They will remain available for our reserves but this will allow them to gain more game time and experience.
“We thank Sheffield for their help in securing these agreements.”
Meanwhile, Jake Spedding will return to the Saints after playing nine times for the Eagles.
Due to RFL operational rules, the centre has not appeared in enough games for Sheffield to be eligible to play for both sides in the final stage of the season.
Five of his matches were on loan and therefore not applicable.
Jack Owens has also signed for the Eagles.
The full back originally agreed terms to remain on loan at Sheffield until the end of the season.
But that has now become permanent after he was released from his contract.
“We wish him all the best in his future career and once again thank him for his efforts in the red vee,' said Mr Rush.
“This will allow them to gain more game time and experience.”