Residents of popular seaside resorts said they were “too scared” to shop because visitors flocked to the narrow streets and ignored social distancing.
On social media, residents described some Cornish seaside resorts as “sheer madness” and “Benidorm on steroids”.
Street marshals patrol hotspots to give social distancing advice.
Visit Cornwall advised people to plan ahead and change their plans if resorts are busy.
Claire Harris, 37, a St Ives resident, said her family were “too scared to go shopping”.
She told the BBC that she had banned her children from going to the main shopping street and the harbor due to the crowds and said it was “the general consensus among friends”.
Jonathan Pitts, who like Ms. Harris manages vacation rentals, said: “Unfortunately I think a lot [of tourists] have the same attitude – that they have come to escape it [Covid-19]. «
Vicky White of Newyln said: “It makes me very uncomfortable going out with my two young children. The sidewalks are very busy.
“It’s sad for the residents not to be able to enjoy the place where they live.”
Many residents of Perranporth have said they feel squeezed out of town convenience stores, some of which have been overwhelmed by large groups.
A woman in her 60s who wanted to be known only as Linda, told the BBC she complained at the headquarters of one of the stores.
Staff told Facebook’s Perranzabuloe community group that they faced an “unreal” amount of abuse from customers for trying to comply with the in-store measures.
Mousehole Harbor Master Royden Paynter said: “Suddenly we were hit by a stampede.
“Everyone’s a little more stressed this year – they’re not budging out of your way.”
But Adrienne Munday, owner of a small business there, said concerns about Covid-19 had been “over-dramatized” in the media and most people were delighted to welcome the “buzz again. summer ”.
An additional £ 500,000 was given to Devon and Cornwall Police by local Police and Crime Commissioner Alison Hernandez in July to help communities deal with the pandemic this summer, allowing the introduction of street marshals.
There were 20 confirmed cases of the coronavirus in Cornwall in the week to July 26, an increase of 14 from the week before.
Malcolm Bell of Visit Cornwall said: “It looks busier than ever, but we are actually below normal peak levels”.
He advised people to “plan ahead and be prepared to change your plans when the sheer numbers of people make social distancing difficult.”