Crusaders assistant coach Brad Mooar will succeed Wayne Pivac as Scarlets head coach next season.
The 44-year-old will join Scarlets from the Super Rugby champions next summer having acted in Scott Robertson's coaching team for the last three seasons.
Scarlets confirmed in July that Pivac would leave his role at the end of the 2018/19 season to replace Warren Gatland as Wales head coach after the 2019 World Cup.
"The opportunity to take on the role of head coach at the Scarlets is simply too good to pass up and is both an exciting challenge for myself, and a fantastic opportunity for my family to experience life on the other side of the world," Mooar said.
"The Scarlets is a rugby brand that's known the world over, it is a winning club with an extremely proud history, passionate fans, and is aspirational in its goals.
"It is humbling to be offered the opportunity to take the reins after the great work Wayne Pivac has led, as he moves on to the Wales job.
"In addition to Scarlets' on-field rugby pedigree, with a strong squad of talented and largely homegrown players, the club represents its wider community with great pride and dedication."
Mooar was previously head coach at Mitre 10 Cup side Southland Stags as well as attack and backs coach with South African sides Eastern Province Kings and Southern Kings in the Super 15.
Scarlets General Manager of Rugby Jon Daniels said: "We pride ourselves in appointing players and coaches that not only perform on the rugby field but also contribute to the ethos and environment of the club and our wider community. Brad's rugby philosophy, leadership style and personality are everything we were looking for in a head coach.
"Brad has been assistant coach with the Crusaders over the last three seasons helping the side to two consecutive Super Rugby titles. Brad has a great understanding of what is required for success and how to build a winning culture.
"Throughout the process we have been hugely impressed with Brad's appreciation of Scarlets' place in the community, his passion for developing players and the research he had done on our heritage."