Michaela McCollum and Melissa Reid who had been working in Ibiza this summer, had previously claimed they were coerced into carrying the drugs by Colombian drug lords who kidnapped them at gunpoint.
They said theywere forced to board a flight from Lima to Spain with 24lb of cocaine in food packets hidden inside their luggage when they were arrested.
So far they have been held at the notorious Virgen de Fatima prison in Lima.
Their guilty pleas at the end of September came on the same day that the UN declared that Peru has now overtaken Colombia as the world's number one coca leaf producer, the raw material of cocaine.
According to a report by the United Nations Office on Drugs and Crime, coca plantations in Peru covered 60,400 hectares last year.