The South West earned more than £9 billion from tourism last year, enough to pay for the entire London Olympics, a new report has found.
The importance of the industry across the Westcountry has been laid bare by the study, which calculates a third of all jobs are dependent on holidaymakers in some areas.
The huge investment has been welcomed but also concerns have been raised as to the fragility of an economy so reliant on weather and the whim of travellers.
Data from Visit Cornwall's in-depth analysis of 2011, Value of Tourism, has now been made available to councillors, though not yet published officially.
It shows that a quarter of all employment in the Duchy now relies on tourism, some 60,921 jobs, thanks to the £1.85 billion spent by tourists. Excluding the value of visits from family, friends and second homes, the value of tourism to Devon last year was £2.15bn, compared to £1.44bn in Dorset and £1.11bn in Somerset.
Robin Barker, director of Services for Tourism and board member of the Tourism Management Institute, said: "These are enormous figures and highlight the essential role this industry has in this part of the world.
"Tourism is not only essential to our economy, but is clearly worth investing in."
Mr Barker added: "The combination of a continued depressed economy, weak euro, extra bank holiday, Royal wedding, jubilee, Olympic and Paralympic games, and of course a wet summer and springtime drought has forced businesses to be 'on their toes' like never before." The total figure in Cornwall was up £240 million on 2010, in part due to the then booming "staycation" market.
The jobs figure compares to 46,000 or 12% in Devon, 29,800 or 12% in Dorset and 23,444 or 9% in Somerset.
In West Cornwall's old local authority area of Penwith, some 8,133 or 31% of all full-time jobs are servicing the holiday industry.
On the Isles of Scilly, the £34 million spent by visitors supports more than 1,000 people, half the population and a massive 92% of all jobs.
The report also shows Cornwall led the way in terms of visitors staying in the county, with more than £1.3bn spent by those staying in the Duchy compared to just under £1.2bn across the border in Devon.
Andrew Wallis, Cornwall Councillor for Porthleven and Helston, where roughly 15% of workers are tourist related, said there is a danger with Cornwall and the South West relying too much on tourism.
He is worried that too many supermarkets, housing schemes and renewable energy plants are being approved, a plan lacking in diversity in employment.
"If there is a massive change, from either domestic and overseas competition, or the poor weather that has inflicted itself on us for the past few years, it would leave a very big hole in the region's economy," he added.
"If the answer is more industry then we need to attract businesses down as we rarely see such applications on the strategic planning committee."
Of the Cornish spend, the vast majority comes from the home market – £1.2 billion – with the still substantial £129 million from overseas.
The much-criticised second homes market generates £4,439,000 and boat owners make a similar contribution of £4,934,000.
Malcolm Bell, head of Visit Cornwall, said the South West figure was unchanged from 2010 to 2011.
Cornwall, however, enjoyed a large rise from £1.61 billion to the current £1.85 billion.
Mr Bell said the increase of almost 15% was above the UK average, which had been around 5%.
"The figures show not only that Cornwall is the UK's favourite holiday destination but the scale of its importance to the local economy and the jobs and businesses it supports," he added. "This year we will be pleased to hold at the current figure – most people are saying they have done the numbers but not the profits, which is just a fact of life at the moment."