The second complainant said she was assaulted by Parkin at a home and that during another incident Parkin forced her to touch him.
The third complainant said she was assaulted by Parkin on a camping trip when they shared a bunk bed.
Crown prosecutor Fiona Culliney told the court that the accusations of historical sexual offending were strikingly similar.
"This is more than just a coincidence," she said, adding that Parkin would be the "unluckiest man alive" if they were.
"In the late 1970s early 1980s the defendant had a sexual attraction to prepubescent girls."
His admission that he asked an 11-year-old if she wanted to touch his erection but that nothing more happened was "rubbish", Culliney said.
Parkin was attempting to rewrite history and paint himself in a somewhat better light, she said.
He only made that admission because it was already in his emails, so there was an "overwhelming case against him" in relation to that.
"In Mr Parkin's mind he can get away with anything," she said.
"He's the golden boy. He's the Olympian."
When he recounted being confronted years later by the victim, about one incident instead two, it was again a lie, Culliney said.
A third victim had come forward upon seeing the media reports in which Parkin had been accused of historical sexual assault.
"This wasn't something she made up because she saw it on the news and she wanted to jump on board," Culliney said.
Her story was consistent with what she had told a counsellor more than a decade earlier — that she was at a camp, that she had hypothermia and that she was assaulted in a bunk bed, Culliney said.
Parkin's counsel Arthur Fairley said the jurors needed to use "robust common sense".
"No matter what way they pitch it in this case it is one word against another's word," he said.
"You don't want to be mesmerised by this numbers game that the Crown submitted to you."
Fairley said one of the victims had struggled to recall where exactly the assault had happened.
"Who has chopped and changed their story?"
The "white elephant" in the room that had to be grappled with was the issue of memory, Fairley said.
Innocuous memories could become more sinister as time passed.
It was difficult enough for a man to defend himself if the charges were current but it was "doubly" so when they emerged decades later.