A shoplifter claiming he had coronavirus to avoid being arrested was among the many call-outs attended by police over the Easter weekend.
South Wales Police said it responded to more than 1,200 Covid-19-related calls on Saturday alone, including a number of people flouting restrictions.
Officers arrested and fined one man who said he had driven from Port Talbot to Mumbles to enjoy the coast.
The force said "a small minority had selfishly put others at risk".
Two men and two women from Cardiff were fined after they called to be rescued after getting lost on a Rhondda mountain.
At Langland Bay, Swansea, four men were stopped after travelling from Cardiff to go fishing as they "wanted to get out after being stuck in all week", police said.
After admitting they understood the restrictions they were fined.
One of them, a 38-year-old, was arrested on an outstanding warrant and remanded in custody.
A mother from Cardiff was fined after her 13-year-old son repeatedly breached restrictions.
Assistant Chief Constable Andy Valentine said: "This remains an unprecedented national emergency in which we all have a part to play, and we are extremely grateful to those who took their responsibility seriously and continued to stay home at the weekend.
"Our officers responded to more than 1,200 Covid-related calls on Saturday alone, and our neighbourhood teams and specialist departments were out patrolling our communities and popular beauty spots throughout the weekend.
"The restrictions are crucial to protecting the NHS and saving lives and I would like to thank people across south Wales for following the government's advice and implore them to continuing to adhere the restrictions.
"Sadly, a small minority chose not to do so over the Easter period and in doing so selfishly put others at risk."