The animals were caught on video climbing over the wall and walking calmly around the attraction in Northern Ireland on Saturday.
One adult chimpanzee passed just feet from four children enjoying a family trip to the zoo.
Manager Alyn Cairns said the chimpanzees soon returned to the enclosure of their own accord.
“They’re intelligent primates and know they’re not supposed to be out of their enclosure, so got back in themselves,” Mr Cairns told the BBC.
“We think what has happened is that the trees in their enclosure have been weakened by the storms and so they’ve been able to break them and use them as a ladder to get out.
“We like things to be natural in their enclosure, to have trees in it, but we will review it.”
Footage of the roaming chimpanzees was posted on Twitter by Elaine Monaghan, whose grandchildren were at the zoo at the time of the escape… see more