Hundreds of pupils were evacuated after four neighbouring schools received coordinated security threats.
St Ives School and Humphry Davy School in Penzance, and Truro High School for Girls and Penair School in Truro, made the decision to ask pupils and staff leave.
Police say the schools received the warning at around 8am but, by 9am, police said they found no threat or risk and buildings were able to reopen.
Head teacher of Humphry Davy School, Bill Marshall, applauded staff and students alike for their reaction to the scare.
In London four schools were also evacuated this morning following calls about "suspicious devices" being left at each of the premises.
A spokesman from the Metropolitan Police Service said the incidents were being treated as "malicious communications".
In the West Midlands a further six schools were reportedly evacuated following bomb threats today.
It comes a week after similar threats were made at four different schools in the Black Country, and four in Bristol last week.
Pupils at a school near Bristol which was evacuated in a health scare have returned to classes.
Emergency services were called to The Manor C of E Primary School in Coalpit Heath at yesterday [Monday] afternoon.
An investigation into what caused the children to become ill is continuing. It is thought to have been a virus.
A primary school in South Gloucestershire is reopening after being evacuated over a possible chemical scare yesterday.
Parents of children at The Manor C of E Primary School in Coalpit Heath have been told to keep them at home if they are unwell.
Fire crews inspected the building but didn't find any problems.
A school evacuated, after more than 25 children fell ill, is due to reopen tomorrow. Emergency Services were called to Manor Primary School at Coalpit Heath this afternoon (July 9th) after children started to suffer from headaches and nausea.
South Gloucestershire Council says gas safety checks are being carried out as a precaution. The school is due to reopen tomorrow.
Twenty six school children have been treated by paramedics at a primary school following its evacuated after several children started feeling ill. South Gloucestershire Council says carbon monoxide poisoning is one of the potential causes being investigated.
South Western Ambulance Service was called to the school this afternoon after to reports of a 10-year-old feeling unwell. They treated 26 children in total for headaches and nausea. All of the children have since been released from their care and none of them were taken to hospital.
Emergency services are investigating several possible causes, including carbon monoxide poisoning.
A school in South Gloucestershire has been evacuated after several children fell ill during the morning. Emergency services were called to The Manor School in Coalpit Heath just before 2pm this afternoon, including two vehicles from the chemical response unit.