The last little climb up the Hawaiian Ironman finishing ramp felt like a mountain to Australian paratriathlon star Lauren Parker.

The 33-year-old achieved a major milestone on Friday (AEDT) when she finished the race — the first time she has raced at Kailua-Kona on Hawai'i's main island in seven years.

Back then, Parker was an able-bodied triathlete and finished second in the 25-29 age group.

Then in April 2017, she suffered serious injuries in a bike crash.

Parker is now a Paralympic medallist and a world champion, but she had always wanted to return to Hawai'i and finish again.

After the 3.8km swim and using a hand cycle for the 180km bike, Parker pushed her racing chair through the 42.2km marathon run.

Her arms just about gave out when it came to the small ramp up to the finish arch.

"I just had to keep moving my arms. It was really hard," she said of the marathon.

"Then that finishing ramp — that was probably the hardest hill in the whole race.

Parker finished the race in an outstanding 12 hours 20 minutes 35 seconds and was the only competitor in the women's hand cycle category.

It was well under the 14 hours she clocked earlier this year in her Ironman-distance debut as a paratriathlete.

"I have high expectations of myself. I had a goal of going two hours quicker than what I did at St George.

"I can't be more happy.

"I'm so happy that I was able to finish in a really good time.

In the pro women's race, Sarah Crowley put the disappointment of a time penalty on the bike to fight back and record a fourth top 10 finish at the historic race, recording a time of nine hours, one minute, 58 seconds.

"It was the most happy, disappointed race of my life, I think," Crowley said.

The 39-year-old was 10th out the water and in the chase group on the bike when handed a five-minute penalty for drafting.