He will swap that for life at Sixways this summer - where he revealed he has already played once before - and the 30-year-old is determined to make the move to the Aviva Premiership a successful one.
"I'm really excited to becoming a Worcester Warrior," said Fainga'anuku. "I'm looking forward to joining the squad that Richard Hill and Nigel Redman are putting together.
"It's a great set-up at Sixways. I actually played at the club before in the Churchill Cup against Italy A so have lots of good memories and know what the fans are like. They are very loyal, make noise and really get behind the team which is great.
"I spoke to the coaching staff about how the want to play and that is exciting too. They want to play attacking running rugby and that suits me with my background."
Fainga'anuku played rugby league as a schoolboy before he was picked up by the Waratahs and put through their system for four years.
He has spent the last season in Glasgow with the table topping Warriors and admits that spell has been hugely beneficial to him.
"I've relished the chance at Glasgow and it's been very good for me," he said. "It's been good to come over here and get real competition. The scrum is much more competitive and more of a focus than back in Australia.
"It's very physical and the emphasis is on forwards in the game plan so I have learnt a lot in the set piece.
"I would love to play for my country more and I feel coming to Worcester will help," he added.
"We have some good front row players in Tonga, but the experience of playing Aviva Premiership rugby will only help me develop."
Fainga'anuku is now aiming to become the latest in a long line of front row stars at Sixways and admitted seeing his name on the back of a Worcester shirt would be extra special.
"I guess my surname is not easy for some so where ever I've played before they have just called me Ofa - even when they announce the teams," added Fainga'anuku.
"I've actually never played for a team with my name on the back so that will be nice - you might need a few more letters though," he laughed.