VOLUNTEERS from Barry Coastguard were called to the Old Dock in Barry following reports of two males In an inflatable dinghy.
The incident happened before 5.34pm, when the team was paged, on Sunday, May 31.
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A Barry Coastguard spokesman said: “On scene we were able to request they left the water as they had been drinking and were without any lifejackets.
“Docks are cold dangerous places.
“During this call a second call came in that youths were jumping into a different part of the Old Dock.
“Our team split to advise them to leave and also to the Dangers.
“Again water and alcohol do not mix and there are many dangers below the surface.”
A South Wales Police spokesman added: £We've had a number of reports of groups of young people involved in anti-social behaviour – and we’re urging parents to check where their children are.
"These reports include jumping into water from a height – known as tombstoning – and underage drinking.
"Not only are these potentially dangerous, but some are illegal.
"They are also a breach of Welsh Government restrictions, for which parents could be liable.
"We know the last couple of months have been tough, but we’d ask you to consider the impact anti-social behaviour may have on other people, on our health service, or on efforts to defeat this virus.
"We are continuing to patrol our communities but cannot do this alone."
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