Authors of a new survey say parents should aim to delay their children drinking alcohol for as long as possible.
Planet Youth found 30 per cent of teens had been drunk in the past month.
Its study also found parents are more likely to allow their children to drink, compared to smoking or vaping.
It took in the views of 15 and 16-year olds across 91 schools in Galway, Mayo and Roscommon.
Planet Youth Coordinator for the West of Ireland, Emmet Major, says underage drinking must be tackled: