People were left hanging vertically on the tracks of a 72ft (22m) high rollercoaster after it broke down.
The passengers were on Rage at theme park Adventure Island in Southend-on-Sea, Essex, when a carriage got stuck just after 14:00 BST on Friday.
The park said its “highly trained team immediately initiated our ride evacuation plan”.
Passengers were evacuated and safely returned to the ground within 40 minutes, the park said.