Connor Scott, Davey Dixon and Liam Johnson have signed up with Dewsbury for 2020 onwards.
Prop Scott joins the Rams from Doncaster and he has signed a two-year deal.
Winger Dixon arrives from Keighley and has signed an initial one-year contract, while back-rower Johnson has signed a new one-year deal with Dewsbury.
Rams coach Lee Greenwood said: “I’m really pleased to get Connor in. I wanted to add a bit of size to our front-row options and he does that.
“He’s played a lot of games at League 1 level and I’ve always thought he was a player that had potential to play higher. He’s got that opportunity now and like the majority of the squad in place, he is here for rugby reasons.
“I thought Liam did well when he came into the team considering the length of time he had been out.
“Davey is an accomplished finisher and is happy to come in and help the team go forward. Despite representing Scotland this autumn, he will slot straight into the start of our pre-season which says a lot about his character and determination to do well here.”