A coach carrying 28 students and a member of staff from St Ives School to a swimming gala at Jubilee Pool was involved in an accident on the A30 between St Ives and Penzance.
The accident happened at about 12.30pm. None of the students or staff was injured.
The coach, owned by the Williams Group, was travelling at low speed on the roundabout when the accident occurred. Cornwall Council said that parents have been informed about the accident and a replacement coach has been sent to collect students and return them to the school.