They were fined for having their hair dyed in the car park of Langland Bay on the Gower Peninsula near Swansea.
South Wales Police said it issued 370 fixed penalty notices over the weekend, with sunnier weather leading to people “flocking” to beauty spots.
The force’s chief superintendent urged people to follow the rules.
Other fines were issued to people travelling to visit seaside areas including Southerndown and Penarth, in Vale of Glamorgan, and Bracelet Bay in Mumbles, Swansea.
A large portion of the fines were issued to people who attended house parties, including 105 to those who went to one of eight gatherings in Cathays, Cardiff.
Over the weekend, car parks at beauty spots were closed to discourage people from visiting.
On Monday, at the Welsh Government coronavirus briefing, First Minister Mark Drakeford called for more “responsible” behaviour.
Under Wales’ lockdown rules, people can only leave home for exercise or for an essential reason.