Children as young as 12 were found boozing at a beach party where another youngster was taken to hospital "dangerously intoxicated".
Police had to attend numerous times in Criccieth, north Wales, over the weekend, where more than 100 youngsters were drinking underage.
Officers released an image of booze seized, which they said was just a fraction of what they found.
The photo showed bottles of Smirnoff Ice and Corona beers as well as cans of Strongbow.
North Wales Police said: "Our Neighbourhood Policing Team attended several incidents over the weekend in Criccieth where a group of 100+ young people were drinking alcohol underage and causing anti-social behaviour at a beach party.
"Children as young as 12-years-old were found to be drinking alcohol underage.
"A 16-year-old male from the Anglesey area was unfortunately found dangerously intoxicated. An ambulance was called by police, due to the ambulance service being incredibly busy the male's parents had to convey him to A&E."
The statement added: "Drinking alcohol underage is illegal and is incredibly dangerous."
