Adrian Attwater and Paul Maris attacked Attwater's partner, Lynette Daly, during a camping trip on a New South Wales beach in 2011.
The case drew attention for the length of time it took to prosecute the men. State prosecutors have apologised for the delay.
It also highlighted issues of how race is dealt with in prosecutions.
'Sincere regrets'
The court determined that Attwater had performed a violent sexual act on Ms Daly that caused her serious injuries while she was too intoxicated to consent.
