The head of Visit Cornwall has warned the county "can't cope" with the huge influx of visitors it is seeing.
"Visitors are not getting a good experience, locals are frustrated and systems can't cope," Malcolm Bell told BBC News.
He added that without a reduction in visitor numbers "we will end up in a place we don't want to go, a very dangerous place which is the quality of experience for the visitor will go down, the price will go down, and we will end up with over-tourism".
"The last thing I want to see is Cornwall being destroyed by tourism."
Experts continue to warn against foreign travel due to the global coronavirus pandemic.
And with international travel restrictions remaining in place for the summer, Cornwall is popular with holidaymakers opting to have domestic holiday, a so-called staycation, within the UK.
Visit Cornwall estimates there are currently about 210,000 visitors in the county, up from a usual peak of 180,000 during summer months.
Last summer Cornwall residents voiced fears that they would become subject to a local lockdown as “unprecedented” numbers of tourists flocked there for holidays.
Locals said they were scared to leave their houses as visitors flood the area, with some comparing beaches to “Benidorm on steroids”.
Local police have urged tourists to be vigilant to keep the area safe.
"We hope you enjoy your summer in our beautiful part of the world," Devon & Cornwall Police wrote on the force's official Twitter page.
"Help us keep everyone safe. Report drug dealing or any other suspicious activity through our online contact channels."
In a statement sent to Yahoo News UK, Chief Superintendent Dan Evans, responsible for summer policing, said: “The tourist economy in Cornwall has suffered significantly in the last 18 months. We are working closely with our partners to support local business and unlock our society safely and in accordance with government and medical advice.
“With the continued uncertainty surrounding travel abroad, we expect an even greater number of people to visit the region on top of those having a staycation, and who can blame them; this is a welcoming community-spirited region and beautiful area thanks to our moors and beaches coupled with the fact that we have one of the lowest crime rates in the country.
“It has been a difficult year for us all and many are happy to see nightclubs reopen and the return of our evening and night-time economy, but please show some restraint and respect to our resident communities and each other.
“We will not tolerate those who think it’s acceptable to ruin this for others, so we are working hard to tackle anti-social behaviour across the region.”
Viv Robinson, a tour guide in Cornwall, wrote on Twitter that she had "never seen it so busy - queues for everything".
The influx of tourists has been rapid since schools broke for summer in July, but holidaymakers planning to visit the southernmost British county over coming weeks could face delays if a protest against second home-owners in Cornwall goes ahead.
Kernow Matters to Us, a Cornish campaign group, has threatened to blockade all routes into Cornwall to prevent non-locals entering the area, in an attempt to ensure every "Cornish person" has a home first.
The group said it was discussing the possibility of blocking routes including the A30 and Tamar Bridge if the problem was not addressed.
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A spokesperson said: "It is within our power to do these things and there is little to stop us."
The comments came as it was announced that a protest will be held in Truro later this month to highlight the growing housing crisis in Cornwall.
It was previously revealed dozens of former council homes are being illegally let as student accommodation and AirBnBs for the sake of profit.
Kernow Matters to Us said this keeps these properties high in rent and inaccessible to local people who need them.
Cornwall Council announced in 2019 it would take legal action against homeowners who did not abide by the covenants attached to the sale of former council homes.
However, there are now concerns that the promise of taking action dropped when council officers were diverted to other roles due to the Covid pandemic.
A Kernow Matters spokesperson said: "We cannot live like this any longer, and we won’t accept growing mass homelessness of people in Cornwall and ever-expanding house prices becoming an accepted part of life.
"We demand action, we demand change, we demand dignity.
"We are not just bartenders, ice-cream servers, and lifeguards, we are people who deserve to be able to rent and buy where we live.
"This is a protest to demand immediate, emergency action from our MPs and Westminster to tackle this crisis.
"We deserve affordable housing and rental properties. Cornwall is not a playground, it is not just a tourist-hot-spot and nice place to live by the beach if you have the cash for it – it’s our home, it’s our culture, our family, friends, livelihoods – and we can’t even afford to live here.
"No more second homes. No more exorbitant rents. No more holiday lets over council homes. Enough is enough."
Formed during 2015 to proclaim and celebrate Cornish culture, history, language and music "whilst speaking out unashamedly for the Cornish", Kernow Matters' members support the Cornish National Minority.