Six Flags Great America is once again implementing a chaperone policy.

The company issued a statement on its website Monday that said the policy will be in place starting Thursday July 17.

Guests 15-year-old and younger must be accompanied by a parent or other adult chaperone who is at least 21-years-old.

The rule will be in place all day July 17 – July 20.

On days following the July 20, it will be in place from 5 p.m. to close.

The chaperone must present a valid government-issued photo identification with date of birth at ticket entry. One chaperone may accompany no more than 10 guests per day.

This includes Great America and Hurricane Harbor.