The Peru 2 are to appear in court again next Tuesday for sentencing.
Michaella McCollum and Melissa Reid could be handed a lower jail term after pleading guilty to charges of drug trafficking last night.
The pair - both aged 20 - were arrested at Lima airport last month with more than 11 kilos of cocaine in their suitcases.
The women had claimed they were forced by a gang at gunpoint to carry the drugs.
Journalist Martina Hanlon who's been following the case in Peru, says the judge will look favourably upon the fact that they have pleaded guilty: