Former Wales international Rhys Patchell, a first five-eighths who can also play fullback, is following in the footsteps of former England Test five-eighths Freddie Burns in taking up a position with the side.
Also joining the side is wing Timoci Tavatavanawai.
Patchell, 1.93m and 92 kg, made his Welsh debut aged 20 in 2013. He toured New Zealand with Wales in 2016 and played two Tests at fullback. He played in the 2019 Rugby World Cup and was part of the Wales Six Nations squad this year.
He has played more than 160 first-class games spread between the Cardiff Blues and Scarlets in domestic rugby.
Patchell said, "The opportunity to head to Dunedin was too good to turn down. Having watched Super Rugby from afar, I'm excited for the 2024 seasons to begin. I look forward to getting started and contributing as much as I can both on and off the field."
Highlanders coach Clarke Dermody is pleased to have terms agreed upon and that he can prepare with the first five-eighths experience reinforced for the side.
Dermody said, "It's fantastic news that a player with the ability and experience of Rhys will be part of our young squad in 2024. We had Mitch [Mitchell Hunt], Marty [Banks] and Freddie with us in 2023 and that worked out well, particularly for our younger five-eighths, who got to experience and learn from proven professionals.
"We see Rhys fulfilling a similar role for Cam [Millar] and Ajay [Faleafaga] next season, helping them to adjust to Super Rugby and develop their games."
But experience was one of many qualities Dermody sought.
"I like his attacking mindset and skillset, which should align well with the way we want to play the game. He defends well, has a sound kicking game and his ability to cover fullback will be an asset to us during the season."
Tavatavanawai, 25, joins the Highlanders from Moana Pasifika after having had wider training group experience with the side and the Crusaders. He has played for Tasman in the Bunnings Cup.
He said he appreciated the chance to play for Moana Pasifika but was looking forward to new challenges and growing his game with the Highlanders.
Dermody said he had a connection with Tavatavanawai from when they were both involved with the Tasman Mako.
"He has been an injury replacement for us in the past, so he knows the club too, and we are looking forward to him showing his skillset under the roof.
"His ability to get a team that all important forward momentum is second to none. His post-contact metres are excellent and he has the potential to be a real weapon on the edge for us and will complement the outside back skills we have in the squad."