A Freedom of Information Act request by the charity found that of 64,372 children in foster care between April 2014 and March 2015, 14,593 had moved carer at least twice, giving a placement breakdown rate of 22.7 per cent.
The figures were provided by 143 councils (68 per cent) across England, Wales, Scotland and Northern Ireland.
The data also shows England and Northern Ireland have the worst track record for placement breakdown. In Northern Ireland, 26.1 per cent of children in foster care moved at least twice, while in England the proportion was 23.8 per cent.
By contrast, placement breakdowns in Scotland (15.1 per cent) and Wales (19.3 per cent) are below the UK average.
The South West is the English region with the highest breakdown rate, with 30.3 per cent of fostered children having two or more placements. Yorkshire and Humber is the next highest at 25.8 per cent.
The charity warns that the disruption caused by placement breakdown is likely to severely impact on young people’s chances in later life, due to the effect it has on their social skills, educational attainment and employment prospects. Mental health problems are also more prevalent in those who have experienced placement breakdown, it adds.
Action for Children chief executive Sir Tony Hawkhead said: “For children in care, moving home is not just about leaving a house. It means leaving family, friends, school and everything that’s familiar to start all over again.
“It is impossible to imagine the damage to a child or young person, who has already had the toughest start in life, to have to move several times a year until they find the right foster carer who will stick with them through thick and thin. We know of children as young as four who have had to move three times in less than a year before finding a stable family home.”
A lack of suitable foster carers is a key factor in placement breakdown, according to the charity, which has launched a fresh recruitment drive for potential carers. It is particularly looking for carers who are able to help potentially challenging young people recover from their experiences.