Almost 3,000 crimes were committed last year by suspects too young to be prosecuted.
The offending by children aged under ten in England and Wales included about 1,300 incidents of criminal damage and arson and more than 60 sex offences, according to figures obtained by BBC Radio Five Live under the Freedom of Information Act.
Children aged nine or under cannot be charged with an offence in England and Wales, although the crime will be recorded by police.
The figures were based on data from 32 of the 43 forces in England and Wales, the BBC said. Of the 2,840 crimes where the suspect was under ten, about half were cases of arson or criminal damage.
There were also 66 sexual offences, including a number of sexual assaults on children under 13. The figures also revealed children too young to be charged were suspected of harassment, wounding and burglary.
Ian Johnston, the Association of Chief Police Officers lead on crime and Chief Constable of British Transport Police, said: "The law establishes that any offence committed by children under ten are not crime.
"Many of these offences are minor acts of damage and by far the large majority of children under ten would not feature in this data.
Youth Justice Minister David Hanson said: "The Government has introduced measures to allow us to intervene effectively at an early stage, to prevent further offending and to help children and their parents, to develop a sense of responsibility for their misbehaviour."