Known for her swimming, Olivia used the opening swim leg to her advantage to take the lead as she headed into the second leg ski.
Corrin, Northcliffe clubmate Lana Rogers and Kibble were out in front but were caught by three others at the end of the leg.
A group of six crossed the line in close proximity for the final leg, the board.
Kibble moved in front and by the journey back to shore remained at the head of the field with Rogers and Corrin in hot pursuit.
The trio managed to jag a wave to put distance between themselves and the rest, and as they headed to shore together, they knew the race would be decided by the run up the beach to the finish line.
Corrin had the inside line, pinned her ears back and powered her way across the sand to the finish to make Nutri-Grain IronWoman history.
“It’s been a long time coming and a childhood dream of mine since I can remember,” she said afterwards.
“Coming around that corner in a sprint finish and seeing the tape up, I just knew I had to grab it first. God, it felt so sweet to hold it up like that.
“I had dreams . . . about how amazing it would feel to cross the Nutri-Grain line in first place, but nothing compares to the real thing.
“Coming over from New Zealand, moving out of home at such a young age, I’ve been working towards my goal for the past five years.
“For it to come to life is just unbelievable,” the 23-year-old said.
Proud father David said it was so great to watch his daughter race live on television both days and to achieve her lifelong dream.
“The whole family is so proud of what she achieved.
“Her fourth placing yesterday (in Round 4’s survival format) was also fantastic and now she’s sitting in second place overall . . . and that’s also fantastic.”
Rogers won Round 4 and leads the overall standings on 109 points, with Corrin second on 82 and Miller third on 75.
Corrin’s Northcliffe and Midway clubmate Cory Taylor was 17th in rounds 3 and 4 of the IronMan series. He is placed 10th-equal overall on 45 points. Defending champion Matt Bevilacqua won both rounds at the weekend to be sitting second on 96 points, just a point behind Ali Day.
The fifth and sixth rounds of the series are at Kurrawa Beach on the Gold Coast on February 3 and 4.