Holidays to Cornwall could be far more expensive after lockdown as tourists will have to pay to stay in their accommodation if they fall ill and can't return home.
The warning was issued ahead of lockdown restrictions easing tomorrow and hotels and other forms of accommodation reopening again.
Visit Cornwall boss Malcolm Bell said all owners had been informed about the new measure.
It is just one part of advice contained in a new information pack pulled together by the tourism board with help from public health officials and Cornish businesses.
Mr Bell told Cornwall Live : "There is advice if you fall ill on holiday and more importantly not to travel if you fall ill. It is about the test and trace and the need to travel home by car.
"If they can't travel back safely using their car they will have to pay for their 14 days in isolation. We have to make that clear as the business will be losing trade."
The warning will be included in information packs placed placed in accommodation for tourists when they arrive.
It includes guidance on social distancing and the importance of avoiding busy crowds.
Mr Bell said: "It has the main message about being safe and reminds people that we are only managing, mitigating and reducing this threat.
"The way to do that is around social distancing and getting the messages around that."
He added: "We are reinforcing the think, plan, book message and we talk about beaches and the idea that they have to have a plan B. If they turn up and the beach is busy, be ready to go on somewhere else.
"We also say that we want you to go to the beach, not go on the beach, regarding bodily functions. And the importance of social distancing at the beach.
"We have strong messages from the RNLI and coastguard about being safe on the beach and in the water. The last thing we need is additional strain on the blue light services."
Between 75,000 and 80,000 visitors are anticipated to visit Cornwall this weekend - around 30 per cent less than average year-on-year.
But Mr Bell said that number was expected to surge to around 100,000.
The domestic tourism industry has welcomed the reopening of businesses after being crippled by the pandemic.
He said: "It will feel a lot busier and the roads will feel busy as we haven't had the run up that we normally have. But it won't be as busy as normal at this time of year.
"I have heard of people wanting to come down at midnight on Saturday but places have been sensible and said come down at the normal times."
Cornwall Council leader Julian German has warned incoming tourists that not all businesses to reopen this weekend.
He said: "For some the closed signs will remain in place the sign of the human cost of this crisis on our communities not only in lives lost but livelihoods too."
