One play expert said the findings showed that the government placed "very little value" on children's playtimes; another called on schools to do "whatever they could" to preserve play spaces - by creating roof gardens, for example.
Information on expansion plans in 82 local authorities shows that 35 per cent of schools that have recently expanded or are due to expand will end up with less outdoor space for children. A further 54 per cent will not lose playing space but will have more pupils using the same area. Just 11 per cent of schools will be able to increase pupil numbers while also providing more playing space.
The number of children in England's schools has been increasing since 2010 and continues to do so because of immigration and a rising birth rate. In April this year, the government published figures showing that 211,930 primary school places were created between 2009 and 2012. Another 299,190 are expected to be available by the end of the 2015-16 academic year.
David Burchett, operations manager of play charity Learning through Landscapes, said access to outside space was "incredibly important" and schools needed to preserve it. "If a child can't run in a straight line because 400 other children are in their way, where are they releasing that energy?" he asked. "Children need space. We appreciate that some schools are on restricted sites, but they should do whatever they can.
"It would be unacceptable to say, `Right let's fit 60 children into a classroom where there's room for 30.' "
Schools often wanted to cooperate with local authorities, Mr Burchett said, but if expansion meant that current pupils would suffer then governors had a responsibility to resist and demand more land. He described a visit to a "horrendous" school site that had a "9ft or 10ft wall around tarmac", adding: "We were chatting to a boy who said, `It makes you feel like you're in a prison.' "
Tim Gill, former director of Play England and a leading commentator on childhood, said: "This is a reflection of what we know already, that educators and government place very little value on school grounds and on children's playtimes and lunchtimes.
"Compared with the Germans or the Nordic countries, we don't pay very much attention to the quality of the environment outside classrooms."
Mr Gill added that educators needed to "sit up and take notice" of research showing that children had a better emotional life when they had a broad diet of playtime experiences.
Of the 957 expanding schools that TES received information about, 335 are losing outdoor space, 520 are not losing space but will have more children in the same area and 102 are gaining space. Based on an average school size of 250, these figures amount to less space per child for 213,750 existing pupils. And even if every school expands by only 30 students, the impact will be felt by at least 25,650 other children. If the data reflects a trend across England, as many as 478,800 pupils could be affected.
Government statistics show that nearly 90 per cent of the primary places created since 2010 are in expanding schools, rather than in new ones.
Sandwell in the West Midlands predicts that its primary population will rise from 27,189 in 2012 to 31,037 by 2016. It has already permanently expanded 12 primary schools and three more have been temporarily expanded. A further 11 expansions are planned. All schools will lose some outdoor space.
"We stay within government guidance as much as we can," said Sue Moore, school organisation and development manager for Sandwell Council. "We have to get Sport England approval, and where the budget allows we've enhanced outdoor facilities."
Although the council tried to follow government guidelines, Ms Moore insisted they were "only a recommendation", adding that there was "a balance to find between providing new places and existing pupils having access to outdoor space".
Gary Redhead, assistant director of schools, planning and resources at Ealing Council in London, said that building upwards was an option on very tight sites, adding that one school had an outdoor space beneath its first floor. Another school might even have increased its available play space because it was expanding by two additional storeys with a play area on the roof, he added.
A spokesman for the Department for Education said the government had brought in "tough new laws" so that councils and schools had to apply directly to the department for permission to build classrooms on their playing fields. Each case was considered "on its own merits", he said.