Andi has representative honours at U21 level for England but was called into the Ireland A squad for the game against Tonga in November 2009.
His accurate lineout throwing and mobility around the park make him a valuable asset to any squad.
Speaking of the signing Cardiff Blues Forwards Coach, Justin Burnell, said:
"Andi has played a lot of rugby for Ulster in the PRO12 and I'm sure he's learnt a hell of a lot from one of the best hookers in Europe, at present, Rory Best."
"So he will be a good addition to our option at Hooker."
"He is signed on two year contracts and further strengthens our front row following the news of the signing of Campese Ma'afu from Australia."