Two were arrested last night as more than 100 people flocked to Cardiff Bay with a sound system, laughing gas and alcohol, despite police warnings.
A man was arrested for obstructing a police officer as he confiscated the sound system and a woman for drunk and disorderly behaviour for the second week in a row.
Detective Chief Inspector Lloyd Williams, from South Wales Police, said: “Cardiff Bay is hugely popular and no one should feel intimidated by the actions of others while they visit.”
A visible police presence was maintained in Cardiff Bay overnight from Friday, August 7 into Saturday morning as part of an ongoing drive to tackle antisocial behaviour in the area.
Large crowds have gathered in the Oval Basin, outside Wales Millennium Centre, during the recent warm weather and following the easing of coronavirus restrictions.
South Wales Police said the majority have behaved responsibly, but the actions of a “small minority” have caused concern and section 35 dispersal powers have been used.
A force spokesman said: “Despite Cardiff Council cordoning off the amphitheatre section of the basin, a large number of visitors still flocked to the area last night.
“Dispersal and confiscation powers were used after some 130 people arrived with alcohol, nitrous oxide canisters and a large music system.”
According to the police, some of those people had already received warnings for their behaviour in recent weeks.
One man was arrested for obstructing a police officer as he confiscated the sound system, while a woman was arrested for being drunk and disorderly for the second week in a row.
DCI Williams said: “As we’ve seen in recent weeks, it was the actions of a small minority who were intent on ruining it for others.
“South Wales Police and Cardiff Council have made it clear that antisocial behaviour will not be tolerated.”
He said extra measures were put in place this weekend, including barriers and marshals.
DCI Williams added: “The vast majority of visitors were respectful of the measures and were supportive of our officers and the efforts being made to keep everyone safe. As a result, the atmosphere was largely positive.”
He confirmed dispersal powers were used and a small number of disturbances were broken up, with alcohol and other items confiscated “where necessary”.
DCI Williams said: “Our policing approach will continue throughout the weekend, so our message to those intending to visit is clear – please visit, abide by restrictions and enjoy.
“Anyone intent on acting in an antisocial or criminal manner will be dealt with robustly.”