Tourism businesses in Cornwall fear they will "run out of money" because of measures to curb the spread of coronavirus.
A hotel owner said a lockdown to fight the pandemic had come at the "worst possible" time for traders.
Businesses joined politicians in urging travellers to stay away to help the NHS cope with Covid-19.
However the government-enforced lockdown means some will lose most of their income for the year.
Kim Conchie from Cornwall Chamber of Commerce said there was “no way” some businesses would survive the summer.
'It's a nightmare'
Stephen Gibson, who owns the Duporth Guest House in Penzance and has been in the trade for 20 years, said the coronavirus shutdown had come at “the worst possible time of year”.
“We can survive a few months but without any money coming in I don’t think anybody will survive,” he said.
Mr Gibson said he had been expecting a busy year and he had so far had £40,000 to £50,000 worth of bookings cancelled and refunded people their deposits.
“It is a bit of a nightmare,” he said. “You never expect it and your income is gone overnight.
“I have two girls who work for me and I am still trying to keep them paid but we have got no help off the government yet. I don’t know what is going to happen really.”
Mr Gibson said his partner ran a cafe, which cost £1,800 a month in rent alone.
“You soon run out of money,” he said.
Mr Conchie said tourism was worth as much as £2.4 billion a year to Cornwall and business leaders were looking at a recovery plan for when the “darkest days are over”, but added: “This will be the end of many businesses in hospitality and retail.
“If the summer is lost then hundreds of retail businesses will just disappear. There’s no way they can survive.”
He welcomed Chancellor Rishi Sunak’s pledge to cover 80% of the wages of staff businesses kept on their payrolls.
'We could do it for a few months'
Gavin Walsh, who runs the Perranporth Surf School, said Easter which usually provided a significant early season cash boost was now a “write off”.
He said he made “90% or more” of his yearly income in the peak tourism weeks.
Mr Walsh said: “I think we should survive it because our overheads are quite low if we are not operating … I think we could (do) it for a few months but we would be very concerned if we lost our season altogether.”
Mr Walsh said he had prepared for the summer season by investing in new stock, advertising and merchandising which “could all be for nought”.
Cornwall Airport Newquay has closed temporarily with all scheduled flights to and from the airport suspended due to the pandemic.
Visit Cornwall said tourism businesses were "facing an avalanche of cancellations and refund requests".
It urged customers to have patience and understanding, while warning some businesses may not be able to issue refunds.
The tourism body said: "Put simply, businesses are struggling and almost all are in a position of ‘can’t pay’ and not necessarily ‘won’t pay’."