Terence Darrell Kelly, 36, on Monday admitted taking the four-year-old from a tent at the remote Blowholes campsite last year.
He faced a magistrate via videolink from custody, pleading guilty to forcibly taking a child under 16.
The matter has been adjourned to Perth District Court on 20 March.
Kelly is also facing other criminal charges, including assaulting a public officer. Those matters have been adjourned to a later date.
He remains in custody.
Cleo was found alive and well in early November, 18 days after she went missing from the campsite.
She was rescued from a property just minutes from her 1 home in the nearby town of Carnarvon, almost 1,000km north of Perth.
Police forced entry to the home and found the little 1 alone in a room, physically unharmed and playing with toys.
Kelly was arrested on a nearby street around the same time. He is alleged to have acted alone and is yet to enter a plea to his other charges.
Police have said he has no connection to Cleo’s family.
Kelly was shackled and accompanied by armed riot squad guards on a charter flight from Carnarvon to Perth after his first court appearance.
The extra security was put in place after Kelly was twice hospitalised with self-inflicted injuries while in custody.
