Madra Michael, aged 10, was travelling with three older sisters when she became ill on Air Canada flight AC-868 en route to London Heathrow from Toronto.
Crew rushed to her assistance and located a doctor and nurse on board the plane. As they tried to revive the girl, the flight diverted to Shannon and landed at 7.40pm.
CPR carried out over a period of time failed to revive the girl who suffered a cardiac arrest.
She was pronounced dead after the flight had landed and the body was taken by ambulance to University Hospital Limerick.
The four sisters who live in Canada were due to travel on from London to Nigeria to spend Christmas with their mother.
Personnel from the Canadian embassy in Dublin travelled to Limerick to help the family and make arrangements for the repatriation of the body to Canada once the autopsy was completed.