Rebels lure Welsh lock to Melbourne
The 30-year-old has agreed to a one-year deal after a 10-year career with the Scarlets in the Pro12, Bath in the Premiership and in Japan's Top League.
Day has made three appearances for Wales since his Test debut against Ireland last August and played at the 2015 World Cup.
"Dom is an experienced lock and an accomplished line-out caller who brings a physical presence to his game," Rebels coach Tony McGahan said.
"He has leadership qualities, having captained Bath, and displays the consistent behaviours and work ethic that will be well suited to our franchise."
The signing comes two weeks after Rebels landed Tongan-born Japan Test No.8 Amanaki Mafi on a one-year deal.
The 198cm, 116kg Day will bring more than 200 games of professional experience to the Rebels.
Day said he was looking forward to joining the Rebels.
"I'm really excited about the challenge of playing for the Rebels," Day said.
"Playing overseas in the Pro12 and Premiership I would always watch Super Rugby and enjoyed the attacking style. I think it's the most exciting competition in the world.
"Super rugby has some of the best and most skilful players in the world and I want to test myself in that arena.
"I've heard Melbourne is an amazing city and I look forward to being a part of the Rebels."
Day will join the Rebels at the conclusion of the Top League season in the new year.
