Michaella, from County Tyrone, and Melissa, from Glasgow, were sentenced in the past hour in a closed court in Lima, Peru.
The pair were caught with the Class A drug – thought to be worth £1.5 million – when they tried to board a flight to Spain from Lima airport, last August.
The girls, both aged 20, initially claimed they had been kidnapped and had been forced to smuggle the drugs at gunpoint.
However, they changed their plea to guilty, in September, to secure a lesser sentence handed down today. If the pair had continued with their not guilty plea, they could have faced up to 15 years in jail.
The girls, who met while working in bars and clubs in Ibiza, have been awaiting sentencing at the Virgen De Fatima jail, in the Peruvian capital, where they have been sharing a squalid cell with 38 other women.
The prison is thought to be one of the toughest in the country, where the conditions are cramped and filthy, and outbreaks of diseases, such as HIV and Hepatitis, are rife.
Throughout their incarceration, both girls have attempted to keep positive however in recent weeks, Melissa has admitted she's started to prepare herself for the worst.
In a diary entry, sent to a national newspaper, she wrote:
“I have prepared myself for the worst . . . I think of how I will be in 15 years . . . and yes it does still scare me.”
It is not yet know which jails the girls will be sent to and if they will be kept together.
We will keep you updated on this story as it develops.