Welham, 24, was entering the final year of his previous contract, but Rovers have moved to tie up one of their most promising youngsters, who has scored 63 tries in 102 appearances for the club.
He said: It’s great to have it all done and I’m just concentrating on playing rugby now.
“There were other clubs showing an interest but Hull KR was always the place that I wanted to be at. I’ve grown up here and the only reason I would have left was if the club didn’t want me. Luckily that wasn’t the case and when they offered me the three year extension I was delighted to sign on the dotted line.
“It was never about money really. I’ve been at Hull KR a long time, I love the place, I live just around the corner and get on great with the players, the coaching staff, the supporters and everyone else involved with the club.”
The news comes as a boost to Rovers as they prepare for Friday’s Super League opener at Leeds.
Head Coach Craig Sandercock said: “It is great news for the club and our supporters that Kris has extended his contract with us. He is a class player who I believe will play for his country. Even better though, Kris is a quality person who is a thorough professional, trains hard and is willing to learn.
“I also believe that the best of Kris Welham is yet to come. It is fantastic that Rovers will get the benefits that Kris brings to the table over the next few years.”