Police have been patrolling beauty spots across the country to ensure strict Covid lockdown restrictions were met as Wales basked in the sunshine.
Officers conducted checks in Swansea while in Cardiff Bay, police were seen seemingly moving people on from the steps of the Welsh Parliament.
Wales is under 'stay at home' lockdown with people allowed to go out for essential reasons and local exercise.
Wales' health minister urged the public not to "throw away their progress".
With fine weather expected all weekend and Wales beating England to win the Six Nations Triple Crown on Saturday, forces and public health officials had warned people not to be tempted to break rules.
North and South Wales Police had issued reminders that lockdown rules were in place, with officers being granted additional powers to stop people visiting beauty spots.
Four people in Merthyr Tydfil were given Covid fixed penalty fines for attending a child's birthday party on Saturday.
Gwent Police said it had been called to Bryn Bach park in Tredegar after reports of people breaking Covid rules. The force tweeted that officers had counted "over 100 vehicles" at the park.
Checks were conducted in Swansea, Cardiff and Vale of Glamorgan to "ascertain the reason for travel", with people being reminded travelling for exercise is against the law.
People face ??60 fines for breaking stay-at-home lockdown rules which ban all but essential travel in Wales.
Wales had the highest Covid case rate among the UK nations before their pre-Christmas lockdown in December.
Now, however, Wales has the UK's lowest infection rate, which fell to 72 per 100,000 people on Saturday - the lowest since September.
Wales' health minister urged the public not to "throw away the remarkable progress" that had been made in fighting Covid-19.
"Please don't throw it away, stick with it because we really are doing something remarkable here in Wales," said Vaughan Gething.
"It's still possible to do a lot of harm to each other and to overwhelm our NHS if we do the wrong thing.
"If we stick on the path, with all of us doing the right thing, we can get through this to release liberties, in a way that is sustainable and have more freedom for all of of us.
"The last thing I want is doing the wrong thing to lead us backwards and undo some of the hard work we have all done together."
South Wales Police said "those believed to be in blatant breach of the rules can expect to be subject to enforcement action" as Wales remains under the strictest national lockdown rules.
"There's a great temptation this weekend, we have great weather and sport going on and this is really a big plea to say, please let's not mess it up," said the force's police and crime commissioner Alun Michael.
"Let's not lose all the gains that have been made. It's great we've seen the numbers coming down but there are still people dying of Covid 19.
"There are some people who are ignoring that advice. That means we need to do more enforcement and police will enforce without fear or favour but the plea is don't let them have to do that, it's not necessary."
We know it's hard when the weather is nice (especially after all the recent wind and rain) but please remember that Wales remains at Alert Level 4.— North Wales Police #KeepWalesSafe ???? (@NWPolice) February 26, 2021
This means essential travel only.
We need to continue to work together to help reduce the spread of #Covid19#KeepWalesSafe pic.twitter.com/JZTNV0LvsU
Swansea University lecturer Simon Williams, a researcher into public attitudes, tweeted to say the good weather would increase the risk of non-compliance and there were "cars and crowds" at his local beaches at Langland and Caswell on the Gower.
But it was "nice and quiet" at Moel Famau Country Park, a popular beauty spot in Denbighshire.
Ranger Ed Sopp said it appeared motorists were heeding the advice to stay away.