Former Newcastle United trainees Craig Robson and Jonny Brain have both penned permanent deals, along with local talent Gary Prosser.
19-year-old Robson, a midfielder, and goalkeeper Brain, also 19, both had trials at Brunton Park last season and both have signed month-to-month deals with The Cumbrians after their release from Newcastle.
Prosser, 18, arrives from local side Kendal Town on a one-year deal, after he also impressed Collins during a trial spell last season.
None of the players will be available to make their Carlisle debuts on Tuesday against Southend.
Another player due to arrive is Brendan McGill.
The Sunderland winger, who is set to pen a one-year deal, spent the majority of last season on loan at Carlisle.
