Jayden McCarthy, who is now aged 18, worked at the privately-run nursery in 2019. He has denied the offences – one count of rape and 13 of sexual assault over a 19-day period.
The nursery, based in Torquay, Devon, has since closed.
According to reports, the court heard that he would commit the offences while encouraging the children in his care to crawl over him on the floor, away from other staff in a toilet block, or when applying sun cream.
The jury was played CCTV extracts allegedly showing the assaults the defendant had committed.
Mr McCarthy was immediately suspended from the nursery after the parents of one child reported an allegation of abuse.
The former nursery apprentice denied all the allegations in police interviews and said he had never touched the children in his care sexually and ‘derived no sexual pleasure from abusing children’.
The trial continues.