Ah You, a product of Christchurch Boys' High School, quickly progressed through the ranks at Canterbury and was capped at U19 and U20 level by New Zealand. He was a key player when the Baby Blacks lifted the IRB Junior World Championship in 2007 (in Belfast) and 2008.
He played for Canterbury in New Zealand's National Provincial Championship, before joining Connacht in 2010. He made his 100th appearance for the Province in the Champions Cup play-off against Gloucester in May 2015.
After qualifying to play for Ireland in October 2013 through residency, he made his international debut in June 2014, during the summer tour to Argentina. He was then subsequently capped in the November games against Georgia and South Africa.
Commenting on the move, Rodney said:
"I'm really excited about the challenges that lie ahead with Ulster. They are a side with big ambitions and are capable of winning silverware in the very near future.
"I feel that the environment at Ulster will allow me to reach my potential and help me to realise my ambitions in the game. With so many players pushing one another for starting places, it will hopefully spur me on to a new level. I feel, at 27, that my best years are ahead of me and I want to push hard for more international recognition too. With the support of my family, I'm looking forward to making Belfast our new home.
"I want to thank Connacht massively for all the support they have given to me and my family over the past five years. It's a fantastic club that is currently competing really strongly in the PRO12 and Europe. I hope they continue to grow and wish them well for the future.
Ulster's Director of Rugby, Les Kiss, said:
"We are delighted that Rodney has decided to commit to Ulster as he will add real strength to our front row department. As a 27-year-old prop, there is still room for him to develop and as a coaching group we will endeavour to get the very best out of Rodney.
"As a squad, when you are competing on a number of fronts, it is essential to have depth across all areas to sustain high performance levels throughout the season. It has been pleasing to see that depth develop in recent months, particularly with the emergence of Kyle McCall at loosehead, and this will further enhance our front row resources."
Operations Director, Bryn Cunningham, added:
"Rodney is an exciting addition to the Ulster squad for next season. His dynamism and ball-carrying ability in the loose will add an extra dimension to our play and gives us another option for the increasingly high demands of professional rugby."