No visitors were ever in danger, however, because Mundu used his day of freedom to sleep in a tree above his exhibit, CNN reported.
He was discovered missing shortly after the koalas were fed and watered Tuesday morning, said zoo spokeswoman Jenny Mehlow.
Mundu is testing his limits as he approaches sexual maturity, Mehlow said.
He was recaptured after the zoo closed and was checked over by a veterinarian.
Swim Week Miami Beach 2014 [PHOTOS]