The Independent Schools Council used the findings from a survey of 270 of its members to call for urgent action to address the lack of sport in UK schools.
On average, pupils at ISC schools, which include some of the most prestigious in the country, such as Eton and Harrow, spend at least three hours a week playing sport, and more than four hours at certain times of the year.
But government figures released last year showed that only two-thirds of pupils in the maintained sector are meeting the target of two hours of sport a week.
The survey shows that 59 per cent of private schools have their own swimming pool, 37 per cent have their own astro-turf pitches, and 31 per cent are equipped with squash courts.
Additional facilities offered by some schools include fitness suites, golf courses, equestrian centres and shooting ranges.