Daily Mail reports even Australia's oldest identical triplets, Florence Welsh, Betsy Audino and Dorothy Murphy (75 years old), showed up.
The celebration welcomed sets of adults, children and anyone in between.
A mind-boggling number of multiples turned out for the day.
Although the celebration reportedly had plenty of performances and rides, Twins Plus also focuses on providing support to the families of those with multiple children.
Karen Willetts, the festival's chairperson, told Daily Mail, "Life in families with multiples can sometimes be difficult because of the extra strain on finances, added stress on relationships, and difficulties with educational outcomes…"
"We want families with multiples to know there is a lot of support around them..."
"They're not alone."
Not being alone is, as you might've guessed, one of the cornerstones of the Twins Plus Festival.
After all, none of the participants know what it's like to lead a solitary life.
As Welsh explained to SBS, she wouldn't know how to function without the aid of her two sisters.
She said, "Without them, I wouldn't have been able to cope."
The convention is one of the world's largest, ranking alongside Twinsburg, Ohio's Twins Days Festival.