A sign which has appeared in Bala reads "go home, rats" - signalling the strength of feeling by people living in the area.
Snowdonia National Park Authority saw "unprecedented scenes" over the weekend which saw hundreds of people walking up Wales' highest mountain in what the park say was the busiest visitor day in living memory.
On Monday, SNPA decided to close its car parks to discourage people from visiting.
Emyr Williams, the park authority chief executive, said: ”Today we will be shutting our main car parks in co-operation with the police and local authorities. We are doing this with the full support of the Welsh Government in order to protect rural communities and health services in the North Wales area. This includes working with them to look at shutting crowded sites and mountains if visitor numbers make it impossible to maintain effective social distancing."
Sunny weather also saw people flock to coastal areas including beaches and promenades around the country.
At his daily No 10 press conference on Sunday, Mr Johnson indicated he was reluctant to ban people from going outside for a walk or to exercise because of the physical and mental health benefits, as long as they acted responsibly.
England's Health Minister Matt Hancock warned people ignoring government advice by leaving their homes to socialise are "selfish and could be costing lives".
He said on Monday would not rule out a full lockdown just as Downing Street also said Boris Johnson would not hesitate to take further action if stricter measures were needed to enforce social distancing.
Coronavirus: Everything you need to know: