The 6’5” forward has been with the Titans since 2015 and previously played at the New Zealand Warriors.
“I am really looking forward to joining the Rhinos,” Peteru told the club’s website.
“I see it as a fresh challenge for me and I am excited about the opportunity to come on board with the team. We have been talking for a while but has speeded up over the last few weeks.
“My family and I are looking forward to coming to Leeds and for me personally playing in a new competition is something that inspires me. Having watched Leeds, I know they have a winning culture and that is something I want to be part of but most of all I am coming for the challenge.”
Leeds Rhinos Head Coach Brian McDermott commented, “Nathaniel is someone we have been keeping an eye on for a while and the opportunity arose to bring him over for next season.
“He is an impressive individual who spoke passionately to us about his commitment to the Rhinos and what he wants to achieve in his own game and with the Rhinos.
“Moving your family to the other side of the world is not something that anyone takes lightly and it is a measure of Nathaniel’s desire to be successful with the Rhinos that he is ready to come over and be part of our club.”