A zoo spokeswoman insisted members of the public were never at risk.
An Irish family visiting Chester was among the visitors in the zoo when the animals escaped at 12.40pm.
They said: “Everybody was told to go because chimpanzees had escaped. We didn't really know what was going on but it was quite scary.
“We were just having lunch and we were told to go into the restaurants and shops, where we stayed for about 45 minutes.
“Luckily we were in there for three hours so we had a good day.”
Other visitors were locked in the jaguar enclosure while staff ensured there were no chimps in the public area. One said: “It was quite calm, people were joking about. No-one was really panicking.”
Many zoo visitors queued for refunds following the evacuation. Staff handed out water to those stuck in traffic and waiting for buses.
One group from Warrington said: “The communication was appalling.
“They didn't tell us anything.
“We had just walked through the front gates and they told us to go into the shop. We heard someone saying it was a red alert.”
Zoo staff faced a tough challenge to regroup the chimpanzees, considered the most intelligent non-human primate, but managed to have them all back in the enclosure within four hours.
No visitors or staff were injured.
Chester Zoo spokesman Rachael Ashton said: “We don’t know how they managed to get there and in the time I have been here I’ve never known it to happen.
“None have got into the public domain but because they are primates we closed the park as a precaution.
“We apologise for any inconvenience this has caused to our visitors."
The zoo reopened this week.