London Irish have signed Jimmy Stevens, Jonny Harris and Alex Lewington from Leicester Tigers on three-year deals.
Hooker Stevens, 22, prop Harris, 22, and 21-year-old wing Lewington have all been dual-registered with Nottingham in the Championship this season.
London Irish director of rugby Brian Smith said: "I've been impressed with what they've already achieved at Leicester and Nottingham.
"If they put their heads down, I've no doubt they can get higher honours."
Smith added: "I'm sure we can develop them further and expect all three will be pushing for a place in our matchday squad."
Stevens appeared for the Tigers in the Heineken Cup in the home win over Aironi in January 2012. He was also a regular feature in the Tigers LV=Cup side this season.
Harris made his first-team debut for Tigers as a replacement for England international Dan Cole in the Premiership win over Leeds at Welford Road in November 2009. He picked up a Premiership 'A' League winner's medal with Tigers in 2010/11 and has also been capped by England at Under-19 level.
Lewington first impressed in Leicester's LV=Cup run of 2011/12, scoring his first senior try with an excellent solo score in the win at Harlequins and then starting the semi-final victory over Bath.
He came through the Tigers Academy and picked up Premiership 'A' League winner's medals along with Harris in 2010/11 and has been capped by England at Under-16 and Under-18 levels.
Meanwhile, the Exiles have also signed young outside back Tom Fowlie on an academy contract for the 2013/14 season.