Carrying firearms, ammunition, knives and weapons of any kind and any other prohibited item. Kings Island reserves the right to prohibit any items at their discretion. Unsolicited photographing or video recording that disrupts a guest's experience or interferes with park operations.

Kings Island enforces strict "High-Fidelity" security policies to ensure guest safety. Prohibited items in 2026 include all weapons (firearms, knives, pepper spray), fireworks, and explosive materials. Outside food and beverages are generally not permitted, with exceptions made only for special dietary needs or baby formula. "High-Fidelity" technology restrictions are also in place: drones, selfie sticks, and professional camera equipment (including tripods) are banned inside the park. Regarding attire, clothing with offensive language or graphics is prohibited, as are masks or costumes that conceal the identity of guests aged 14 and older. Additionally, loose items are strictly forbidden on most thrill rides; items like cell phones and keys must be secured in buttoned pockets or left in lockers, as "High-Fidelity" sensors on rides like Orion or Diamondback may trigger a safety shutdown if a guest is seen with a phone out on the lift hill.