Lloyd, 20, can play as a centre or second-row, and he has joined up with the Vikings’ pre-season programme immediately.
Widnes assistant coach Mick Cassidy is pleased the club have secured one of their long-term transfer targets.
“Rhodri is a player we have looked at for a while and we think he fits in well with what we are trying to achieve here at Widnes Vikings,” said Cassidy.
“He can play centre but can also give us cover in the back row. He gives us plenty of strength and we are expecting big things from him.
“He needs to play week in week out and hopefully we can give him that opportunity. We are looking forward to working with him and developing his talent.”