A survey of 79 one-week package holidays for a family of four at a four star hotel in Tenerife, Majorca, the Costa del Sol and the Algarve found that prices increase by up to 115 per cent compared with the same trip taken two weeks before schools close for the summer.
Travel money provider FairFX, which carried out the research, said it showed how travel companies “exploit” parents by hiking prices as soon as schools in England and Wales break up.
On average, the cost of holidays rose by 35 per cent but the investigation also found that the biggest hike was a 115 per cent increase in the cost of a Thomas Cook package holiday to Majorca from London and a 104 per cent increase in a First Choice holiday to the Costa del Sol flying from Birmingham.
The study found that Leeds Bradford Airport was the most expensive regional airport on average for all the destinations, though its price hikes of around 34 per cent were below the national average.
FX compared the summer prices for holidays leaving from regionals Cardiff, Exeter, Bristol, Birmingham, Leeds and Newcastle.
In most cases Leeds was the most expensive but did not see the biggest percentage increase in prices out of the regionals.
Package holidays from Birmingham saw the highest regional average price increases at 43 per cent, and those flying from London saw average prices become 45 per cent higher after the start of the school holidays.
The figures come as many parents make plans for summer holidays abroad, but face fines if they take their children out of school for unauthorised absences.
Responding to the survey, FairFX chief executive Ian Strafford-Taylor said: “It seems parents are being held to ransom by travel operators when it comes to summer holidays.”